[paulgb]

But it is gambling, it's just that you're gambling your interest foregone rather than the principal.

Back to my original question, though, I don't see what real-world problem it solves to add stochastic variability to interest payments.

[prohobo]

That's not what my point was about. The point was autonomous services, and I also outlined an idea for one that would have real-world benefit (if properly designed). You can argue that there are no "useful" services yet, but not that there will never be any.