As for the original topic the only real reason to buy the game on steam is if you really only use the steam store to buy games (some people really do this anymore). I have heard though steam takes like 30% cut so it is always better to support, especially small, devs, and if it was to ever fail, you could lose access to many of your games.
As for FM I always wanted to get into it, I enjoy football when I catch a game I always enjoy watching, but I literally have no idea what's going on half the time. I can fully understand what it's like for most my friends when they watch Baseball or American Football with me and seem to have no idea what is going on.
