I wanna preface with the fact that I really...REALLY don't like the minions. They were good for the first movie, and then after that, any charm that they had was kinda...gone.
But they were definitely integral to the plot. The thing is, you can argue that they can be, as was said earlier, replaced by robots or gadgets. But really, they...can't. The point of Despicable Me was to poke fun at classic villain tropes, like stealing national monuments for no reason and having evil lairs. And, as we all know, the classic villains have minions. Annoying, dumb minions that all look similar because they're supposed to be expendable. The minions were necessary to have that "villain cliche" for the satire.
Porgs aren't integral at all. They serve no purpose but to look cute and sell merchandise. Cut out every scene with a Porg from the Last Jedi, and the plot will not suffer in the slightest. Cut the minions out of Despicable Me and suddenly you're missing half the movie.
But gosh dang it, if I don't love those stupidly cute space penguins.
