Comment by Bender
Maybe this will check a box in some OpenStack cluster but it wont work for me personally. Anything sensitive I use physical servers. Once I am on a VM of a physical server that is not mine then my data is their data. It is just turtles all the way down and there will always be a way to obtain data. Whats more this is required for lawful intercept and authorities expect providers today to be able to live copy/clone a VM. There will always be a back door and when authorities can access the back door, so can the providers and malicious actors. Even more unpopular is that to me encryption is just mathematical obfuscation a.k.a. magic math and the devil is in the implementation details remember WEP and DVD encryption? Just like cell phones there will always be some simple "debugging" toggle function that can bypass it.
Why do you trust your physical servers? Do you believe it is impossible for a backdoor to exist in the CPU's Management Engine? Do you inspect the contents of every single network packet entering and exiting? Do you have a way of blocking or inspecting all electromagnetic radiation?
Confidential computing is trying to solve the very problem you are worried about. It is a way of providing compute as a service without the customer having to blindly trust the compute provider. It moves the line from "the host can do anything it wants" to "we're screwed if they are collaborating with Intel to bake a custom backdoor into their CPUs".
To me that sounds like a very reasonable goal. Go much beyond that, and the only plausible attacker is going to be the kind of people who'll simply drag you to a black site and apply the big wrench until you start divulging encryption keys.