For me, personally? I do it for kicks. But in general, there do exist many data loads in the world which are valuable to the holder, valuable enough to be worth

For me, personally? I do it for kicks. But in general, there do exist many data loads in the world which are valuable to the holder, valuable enough to be worth the low cost of a backup, up until time T in the future. After T, however, they become more of a liability than an asset to hold. A self-destructing backup model is the obvious fit for such situations. Both the positive-sum and the negative-sum periods need to be considered to truly safeguard your data properly.