I guess it's because "Play in browser" games don't need any kind of downloads, and since people may be a little bit lazy they probably prefer that kind of games over the ones that you need to properly download and un-zip. I'm kinda at fault too, since I played most of the browser versions of the games that have a high number of ratings. But they really suffer with quality loss- the games are really butchered and feel like a watered-down version of the full game (like the last wizard tower), when in reality they are really good games.
So yeah, it probably has something to do with being able to play them in browser. Doesn't make them any less better, tho! ComaX is a banger.