Is it worth it? If you're spending the nights and money anyway, yes. The return isn't great, but it's better than zero. In most programs the points don't expire unless there's no activity for a year or more. Eventually, you'll have enough points for a free night or two. Comes in handy, even if you're not using it for yourself.

With 15-20 nights a year though, maybe consider Hotels com and their loyalty program. No brand commitment. No real status perks, but you're not likely getting much of those anyway.