Steer clear. The EA download system is CRAP. You need several different accounts, and even then it's hard as hell to redownload games. Don't believe me? Before buying the game, pretend it's 1 year from now and you want to redownload the game. Try to find it on the EA site.
Steam is the only way to go.
I dont know if you deliberately ignored the other posts that mentioned perfectly reasonable ways to back up the files or not. So I will pretend its 1 year from now. O wow look at this, i have my saved folder where the install files are. Wow, magic! And and i just need to logiin into my ONE account to play online? More magic!
Apparently you lack the magic needed to use EA's digital download system.