It just doesn't make sense why games need to be on disc anymore. I don't need discs for my Mac anymore, so I shouldn't need them for games on my PS3.
So buy them. There are plenty of ps3 games available for download. I downloaded Infamous from psn (after renting it from gamefly actually) and I know other games are similarly available (LBP). I'm not referring to the "arcade" games, those smaller, $10 games but rather full retail games.