I mean, I find fanfic benefits from the third POV because we don't really want to enter the story so much as watch it happen. Be it gen or mature, if its not a reader insert we are usually looking to look from an eagle eyed view. Each POV has it's uses, but in the fanfic space it's a strange choice to use first.

Though first isn't nearly as intense as second when it comes to telling you what to do. First has its uses- like the Percy Jackson series. I don't think it would hit as hard without Percy's sass in the first person. It really depends on what you read for. Some romance novels are thinly veiled self inserts. Those should be first. PJO is first because its meant for kids: it's easier to relate and immerse yourself in a story when you get to feel like you're there too.

I read because I want to watch, it's why I use third most often. But I've written lots of non-fanfic work in first. It sets a different tone, and follows different conventions that might work better for what I'm using. I think short stories do really well in first. Like a friend telling you a story.

but also. you're so real. if all i read was first POV id lose my mind