No, you just need something that has reasonable management and reputation and is familiar-enough for your potential users. Some country codes are happy to have

No, you just need something that has reasonable management and reputation and is familiar-enough for your potential users. Some country codes are happy to have unrelated users, and some are not. .ninja was polluted by spammers so fast that many email servers just drop the entire TLD on sight. If most of your users speak something other than English, you might find any number of good words going unused.