To me, personally, SC is not a game. Because it's alpha, you are supposed to test it, not play it - a any gameplay will get wiped. For the same reason, alphas and betas to me aren't games (in "computer game" sense, in broader "game" they are - but then anything can be game, right now I am in a middle of an arguing game, for example). Just to clarify - Early Access to me IS a game, because the devs then say "It's buggy, but you are supposed to play, not test".
So when I played WoT beta, WoWs beta, etc - I had some fun, but I wasn't playing the game, I was testing. I also wasn't playing as I later played in the release versions. I don't do the same stuff in Elite betas as I do on live Elite branch. To me, this is the difference.