They are taking measures to ensure its not too easy to impersonate other users. Seems like a good idea to me.
That certainly does seem to be their goal, but, imo, it's a bit extreme — especially given the context.
Which context ?
In Wikimedia projects (and MediaWiki systems in general) you actually have to pay attention to other people's usernames (when working with histories and in article discussions), and at least in Wikipedia long long time ago there was a lot of trolling/vandalism where people impersonated other users (particularly the admins) and made bunch of sockpuppets with tiny variations in names when they got banned. So this rule makes sense.
That's actually really cool that they do that. Reduces the ability of people to scam because they cannot pick intentionally-similar usernames.
try "Karushifā"
the scenes when one won't be able to choose 5318008.
Ha, that username is apparently not allowed. They require that a username contain at least one letter.
That error message is pretty bad, characters does not mean letters.
They are taking measures to ensure its not too easy to impersonate other users. Seems like a good idea to me.
That certainly does seem to be their goal, but, imo, it's a bit extreme — especially given the context.
Which context ?