Not saying it couldn't be very useful for the data-heavy consumer. Just guessing this is more of an enterprise play than anything else. :)
I personally don't have a feel for enterprise archival requirements (vs. backups), but I do know there are a whole lot of grandparents out there with indifferently stored digital media of their grand-kids (I know two in particular :-); the right middlemen plus a perception of enough permanent losses of the irreplaceable "precious moments" and AWS might see some serious business from this in the long term.