The X app is dispensable absolutely but what about your banking app and other stuff. One of my banking apps was telling me how to make it even easier enabling the front camera and I bet some months from now that won't be optional anymore. Sure, I can use another bank but banks tend to do these things and politicians tend to push them that way. And it's not about you and me. We might jump through hoops to live on a bitcoin standard but in a world where we are the unicorns that still use open tec. Bitcoin is dead. If people have to hunt old computers at garage sales to be self-sovereign, killing bitcoin becomes very feasible.
Bitcoin needs pervasive open computing. Hardware-based attestations do not stand against that in principle but in practice it often does. A smart phone has many chips and one of those can be - decoupled from the main functioning of the device - provide attestations but if you want it to attest to the OS being locked down then ... well ... you run a locked down OS or don't have attestations.
