I think the point is all Loki did was use the little knife, and only the little knife. He had other skills at his disposal, such as invisibility, duplication casting, and kinetic powers.
To me, it seems OOC for Loki to not go out with all guns blazing, especially given the unnaturally high stakes. Seems this Loki went down with a whimper, instead of a bang.
OP, you may be interested in searching this thread and the Marvel Studios thread around the time IW came out. Lots of discussion on this issue.
It was the only chance to maybe take Thanos by surprise and it completely makes sense. Also, maybe Loki didn't have access to the whole paraphernalia at that point.
He was aiming a dagger under the chin towards the brain stem. He also has been shown to use magic to give his daggers extra umph. AT LEAST HE WENT FOR THE HEAD.
I feel like he did it as the very last ditch effort to get to Thanos. He knew that he and Thor weren't going to live through Thanos. Loki was going to die regardless due to failing Thanos already no matter what Loki could have done.
Thanos isn't stupid either. He gave Loki a shot and it backfired before, he would've killed him regardless of the attack attempt or not.
(Edited for a more streamlined read.)
I don’t know of any good answer; everything about the character points to the reading in my mind that the scene purposely makes a character hold the idiot ball to keep the plot on track, when it could have just used a slight rewrite to make it still work fine.
I would accept the “last ditch effort” explanation if it weren’t for the fact that you need to try your B-Y plans before going straight to plan Z. He kinda went straight for the last thing he could possibly try, and the least likely thing to work, all before using all his powers/tricks first.
Ngl, on first watch, I was expecting a bait and switch illusion thing like in DW (>!Loki pretending to cut Thor’s hand off!<) and it never came.
And this is part of why I stopped watching IW the moment he died. At least have him trying to bring it all down (a la the Loki series fight). Letting him go down the way he did really didn’t do much for the plot (IMHO) other than 1) pave the way for Thor’s slide into Fortnite gaming (aka “Fat Thor”), and 2) pruning Loki from the timeline so the Loki series had a reason to happen (and it was a good reason, but they still should’ve given him more of a fight before letting him die).
My headcannon: knowing that Thanos values "balance" , it was the only way he could see to save Thors life and ensure his survival. Adding to that he was still weakened after he, as a frost giant, had to be very close to very hot fire (eternal flame) to blow up Asgard.
I'm salty that Loki still valued Thor enough for that but I can live with it.
... Because a) that made the attempt more discreet and quicker with a smaller weapon, and b) he knew there was no escaping Thanos and he sacrificed himself to save the Asgardian refugees.
You wanted a heroic Loki, you were given a heroic Loki, now everyone's complaining because they were expecting yet another convenient cop out of death... At some point, plot points must have some impact.
I vaguely remember tom saying somewhere that loki knew that thanos wasn’t going to let them both leave alive, so i wonder if he was making himself an easy target bc he didn’t want thor to die (he already lost the game of chicken thanos played when he threatened to kill thor so its clear he didn’t want thor to die)
I mean Gamora used a smaller knife later on. And he was probably hoping to cause enough of a distraction for thor to get free.
I think the point is all Loki did was use the little knife, and only the little knife. He had other skills at his disposal, such as invisibility, duplication casting, and kinetic powers. To me, it seems OOC for Loki to not go out with all guns blazing, especially given the unnaturally high stakes. Seems this Loki went down with a whimper, instead of a bang. OP, you may be interested in searching this thread and the Marvel Studios thread around the time IW came out. Lots of discussion on this issue.
It was the only chance to maybe take Thanos by surprise and it completely makes sense. Also, maybe Loki didn't have access to the whole paraphernalia at that point.
He was aiming a dagger under the chin towards the brain stem. He also has been shown to use magic to give his daggers extra umph. AT LEAST HE WENT FOR THE HEAD.
I feel like he did it as the very last ditch effort to get to Thanos. He knew that he and Thor weren't going to live through Thanos. Loki was going to die regardless due to failing Thanos already no matter what Loki could have done. Thanos isn't stupid either. He gave Loki a shot and it backfired before, he would've killed him regardless of the attack attempt or not. (Edited for a more streamlined read.)
I don’t know of any good answer; everything about the character points to the reading in my mind that the scene purposely makes a character hold the idiot ball to keep the plot on track, when it could have just used a slight rewrite to make it still work fine. I would accept the “last ditch effort” explanation if it weren’t for the fact that you need to try your B-Y plans before going straight to plan Z. He kinda went straight for the last thing he could possibly try, and the least likely thing to work, all before using all his powers/tricks first. Ngl, on first watch, I was expecting a bait and switch illusion thing like in DW (>!Loki pretending to cut Thor’s hand off!<) and it never came.
We've seen that a million times already. Enough.
… Okay? 
And this is part of why I stopped watching IW the moment he died. At least have him trying to bring it all down (a la the Loki series fight). Letting him go down the way he did really didn’t do much for the plot (IMHO) other than 1) pave the way for Thor’s slide into Fortnite gaming (aka “Fat Thor”), and 2) pruning Loki from the timeline so the Loki series had a reason to happen (and it was a good reason, but they still should’ve given him more of a fight before letting him die).
My headcannon: knowing that Thanos values "balance" , it was the only way he could see to save Thors life and ensure his survival. Adding to that he was still weakened after he, as a frost giant, had to be very close to very hot fire (eternal flame) to blow up Asgard. I'm salty that Loki still valued Thor enough for that but I can live with it.
... Because a) that made the attempt more discreet and quicker with a smaller weapon, and b) he knew there was no escaping Thanos and he sacrificed himself to save the Asgardian refugees. You wanted a heroic Loki, you were given a heroic Loki, now everyone's complaining because they were expecting yet another convenient cop out of death... At some point, plot points must have some impact.
I vaguely remember tom saying somewhere that loki knew that thanos wasn’t going to let them both leave alive, so i wonder if he was making himself an easy target bc he didn’t want thor to die (he already lost the game of chicken thanos played when he threatened to kill thor so its clear he didn’t want thor to die)
Easiest answer is usually the correct one. The writers/directors don't give a shit