Achieving real-world service objectives via cloud infrastructure requires a different approach to architecture, data management, process design, service ownership, availability, cost management, the list goes on.
Some uses of cloud services are superficially comparable to old-school bureau computing. But to say it is "just someone else's computer" is trite, grossly misleading and downright bad advice, because treating it as such will get you burned.
I think we are on the same page here. How about - it's nothing more to it than someone else computer. With all the risks and benefits.
If you have the right workload, it is super awesome.
If you have a reasonably matching workload and you can spend spend time on all the things you counted, it's also probably good but it's far from a clear-cut certainty.
If you have heap of legacy systems you will basically need to rewrite a lot it to make it work, and then it might not be worth it at all. This is the case that is oversold.
That would be computerless computing - seems to a harder problem to solve... P2P was about using non-dedicated computers. It's like the antithesis of the currently marked cloud solutions isn't it?
It's a genuine business case, as running a lean and secure server farm is no child's play, but it's also oversold so much that my eyes hurts.
Actual serverless computing would be implemented as p2p. Possibly interesting in a typical EvilCorpesque large corporation.
Besides, Seti@home (Boinc) have been doing serverless computing for almost 20 years and it wasn't the first implementations.