> Those are not mutually exclusive. I may be interested to know that @emmanuelmacron and @emmanuel_macron are both real persons but I’d also want to know that @emmanuelmacron is the famous one while the other is just an homonyme. Blue Check symbols are also a lot useful to distinguish real brand accounts from fake ones.

This would limit the population of "people who can trick others that they are Emmanuel Macron" to people named Emmanuel Macron, which is such a small edge case I don't think it's worth considering. Add photo validation to ensure that a profile picture is actually you and the problem is pretty much solved.

For brands, it doesn't seem impossible to do verification for any brand through DNS proofs or something like that.