Great setup, but if it's not in the clear you still have to decrypt it to sign. So you are carrying it plus the way to unlock it and it still comes out every time. Same exposure, more steps. If the only safe option is DIY, most people won't self custody. They will sit on exchanges and ETFs and Bitcoin ends up with a handful of custodians. Tin foil hat on, I reckon that's what a lot of these attacks are after.