Would it be ridiculous to suggest that this is no different to requiring all usernames to be composed of CJK characters? That would be inconvenient and exclusiv

Would it be ridiculous to suggest that this is no different to requiring all usernames to be composed of CJK characters? That would be inconvenient and exclusive, no? (also, a nitpick: "just ascii" is still the wrong approach, since you probably don't want people putting BEL or NUL in their usernames)