Its a leap that folks desiring cloud storage will want to host their own some day. I think its a little like "I want an open-source car, so when they switch back to horses, I'm ready!"
It's less like that than it is "When we're operating at a scale that makes it more affordable to own hardware than to lease, then it'd be nice if we could."
The other unmentioned benefit is in scratching your own itch. If you want feature X, and Amazon won't give it to you, you can develop it in-house and host it yourself.
