Organizational leaderboards, newsfeeds, solution lists ("Clans"?)
So friends/coworkers could have more incentives to participate.
Had someone recommend codewars on our slack channel but participation kind of fizzled out.

Premature generalization, I guess?
If something else unrelated to logins wanted to do the same pattern check, they could reuse this function without having to refactor any variable names.
Doesn't really matter for katas, I admit, force of habit :\

Parens are only necessary when you want to capture the results for later use. e.g. If you wanted to find out what exact value you matched. If you only care about validity then parens aren't required.