I think it's primarily the capability to explain it that you lack. And yeah, the world's most advanced supercomputer can't steal your bitcoin, but you're still vulnerable to the old fashioned $5 wrench attack. Or being jailed until you make the payment or give up your keys. Or seizure of physical assets. Or denial of access to benefits or services. Or a dozen other things. It's true the government can't just seize your bitcoin, but they still have the power to make life extremely miserable until you do what they want.