If you’ve ever wondered about the importance of sidekicks, watch Spider-Man: Homecoming. Spidey has never had what would be traditionally considered a sidekick, but he has always had a close friend or two who basically take that role. In Homecoming, that’s his buddy Ned, who is pretty much just as unpopular a teenager as Peter Parker – so, obviously, they’re a great fit. But he’s not simply there to keep Peter company or provide comic relief.
Ned is the everyman, the guy who has the questions and wants the details. He provides exposition for the audience to make sure everyone is following the story and knows what they need to know without it becoming some long, drawn-out monologue. For example, in Homecoming, Ned asks Peter about his powers and the radioactive spider in a really short conversation while they’re walking to school. And that’s it, that’s all the origin story you get in the movie. And it works! There’s also a scene where he’s hanging out with Peter at home as they just happen to be tracking Vulture’s crew. It’s a segment that could have been done with just Peter staring at the tracker, but how boring would that have been?!
Pick any movie where a sidekick or friend plays a relatively prominent role and you get the same effect – they are always there to provide exposition for the audience. (And it’s not just in superhero films.) In many cases the main character or hero explains what they’re doing to the sidekick or the sidekick asks questions to get the full story and find out what’s going on. That’s how the movie makers (and often comic book writers) make sure that people are following along and certain plot points are made obvious enough to follow. Of course, it also means the audience finds out only as much as the sidekick asks about – and they always miss something.