It creates that "one big chatroom" vibe from old twitter, while Mastodon feels like a bunch of people microblogging next to each other

People just join it thinking it's Jack Dorsey's next twitter.

Portable accounts and being able to add third party layers to your feed for moderation and sorting algorithms. At least that's their design goal, idk if it's actually implemented because I never got an invite after like half a year.

Main positive thing I’ve heard is that it has a different vibe and culture that some might find more open and fun and sometimes even less problematic. That’s just hearsay, I’m not on there, but I’ve heard it from people I like and trust (on masto).

Lots of semi naked dudes and I still don't know why!

More non political stuff most likely.

Being invite only makes it seem like some kind of cool club.