Unfortunately, I see no advantages to installing the Mac versions, unless you don't have a Windows license. In fact, I'm a somewhat hard core gamer and I finally got frustrated with trying to play games in OS X. Because I end up having to boot into Windows for the games that aren't supported on the Mac, it felt like a waste to even have them loaded on the Mac side.
I suppose if you want to get a quick game in and then jump right back to your work in OS X, that could be an advantage, but games really do perform poorly on OS X compared to Windows.
I finally built a completely separate Windows box just to play games. That way I don't have to boot back and forth between OSes. I wish Apple would start taking serious gaming more seriously, because OS X is definitely not optimized to handle games as well as Windows does.
I hate to say it because I love OS X, but Window is still the way to go for games.