Overall I agree with this, but I think there's a genuine need for a general self-destruct mechanism. Having a key confiscated or taken by force should be preventable in some way, and even if I have a backup key, there needs to be a low-friction way to make a key unusable and unrecoverable.

It would also be nice to have a way to quickly de-register a lost key. Having a back-up is great, but it's still a pain to go de-register the thing on each individual provider's platform. And if I miss one provider it could easily be game over. I'm not a huge fan of centralization but a single registry for dead keys would make a lot of sense for the different providers to cooperate on.