Yes: I am well aware of this part of Twitter culture, as someone who has like half a million followers and a verified account on that platform. And yet,
somehow, knowing a ton of people like doing it doesn't convince me that it makes any sense to allow it willy-nilly and in combination with this other feature, given the functionality of verification and the expectation that someone with a blue check next to their name is who they say they are.
The concept of being verified had meant that your display name and bio--not really your username, which could be a random string of characters; though, it was, of course, relevant--was a readable representation of who you are; so, if you can arbitrarily change that to anyone you want, it clearly doesn't do what it claims to do as people will see your new identity and your still-random username with a blue check. That changing your username would immediately lose your status and yet changing your display name and bio only does so if you abuse the privilege is non-sensical and somewhat ridiculous as it misses the entire point.
It also (but I already said this) seems fully reasonable to me that, if you want to be verified, you will simply not be able to take part in this mostly-silly and entirely-optional part of Twitter culture in exchange for having a blue badge that is supposed to ensure that people who see a username like "@MuscleNerd" knows it isn't Hank Green merely because they changed your display name to such. If you like dressing up in costumes, and you also think verified badges serve a purpose, it simply isn't unreasonable that you would need to have your costume verified to not look like someone else before into gets a blue check.
(Note: MuscleNerd isn't verified as he refuses to tell people his real name, so of course he can't do this, but I use him as an example because he is--or at least was, back years ago--both famous and has a glorious username that popped to my mind, as of course anyone working in science could have decided to go with "@MuscleNerd" as their username, so seeing the username by itself means nothing.)
Or, to be an asshole about it (as you were in your comment): "Surely, you realize that someone's username might have no correlation with their real name, and so the verification shouldn't have anything to do with the username and it's presence on a Tweet doesn't help prevent confusion. Hell: if people are expected to know someone is fake despite having a blue check just because their username is wrong, they clearly didn't need the blue checks in the first place as they already know the right username :/. If this is news to you then maybe you don't understand the issue as well as you thought."
