I believe you could still judge their suitability as opponents by looking at their win/lose stat. If they lost 200 chess games, and won 5 - well you could easly tell that they are probable not too good at Chess.

"People dont play to get a rating" - well some do, or they would not cheat to try to get their ratings higher. The way they cheat is by using free pawn accounts, and this would just take that away.

And if they are playing just for fun, then they don't need their ratings anyway! :-)

I like ratings - I try my best to keep my ratings good while at the same time have fun!