Luke did something we’ve never seen any other Jedi do before. He projected a solid version of himself across unimaginable distances and could interact with Leia and even Threepio. That had to come with a price. In the end, Luke saved the day one last time and went out a hero.
Maybe we had never seen this before because it makes alot of things obsolete.
If the jedi (and throught the time there were a lot of jedi more powerful than Luke) could project a solid self to anywhere in the galaxy they could enter enemy ships ore bases and sabotage it or so. Many things in the war would be handled differently.
Did you miss the part where doing this killed him?
Not trying to be snarky either really, because I actually did miss that on my first viewing. Or at least hadn’t fully wrapped my head around it yet.