> It's not a nice problem to have. It is not a problem.

I think you misunderstand his word usage, though you're seemingly following the same process.

A "nice problem to have" is one that results from having success. Yes, he doesn't have the problem now, because he's got no users, so indeed, having to reset the passwords of existing users would be a "nice to have" problem.

You're already in the "nice to have" zone (clients with problems to solve!), and you want to fix those problems brought on by popularity.