I know you can still back up the files if you install the hard copy but I'm not sure about the cloud storage...I've never done anything like that. I do know there's a lot of online interaction and you can share individual Sims and lots online, so you could download those later, but their traits and skills would be gone.

I'm guessing the store price is the cheaper of the two? I totally understand $12 being a big difference. Personally, I would go for the cheapest option I could find.