I was having a conversation with my oldest daughter over the weekend. She is a young mother with two little kids. All of her photos are digital. I highly encouraged her to get prints made and put them in albums.
"Its ok...I have everything on Facebook and that's secure" she said.
"Can you still log in to your MySpace account?" I asked.
Even if, in theory, your digital files (be they cloud based or not) will be perpetually accessible, there are a thousand human factors that can get in the way. In my daughter's case, she admitted that she couldn't even recall her MySpace user name, and she no longer has the email address she had at the time, so password recovery is probably not possible.
Print. Your. Pictures!