[JAlexoid]

That's a very idealistic opinion.

People don't care about usernames and other crap. They want an easy option - enter email, communicate over email and be found using email. This isn't their banking app or anything that important.

[filleduchaos]

Nobody "wants to use their email". They just want to start using whatever app or service they're trying to connect to as quickly as possible - why exactly do you think "Sign in with X" became so popular in the first place?