Thinking you will know the day and hour of your death is extremely bad estate planning. Any wealth is potentially inheritable, because you can die at any time.
(And yes, that is a shortcoming of cash. Which is why we've invented other ways to store value, and approximately nobody stores their money in random holes on other people's property.)
Uh I mean, not that I'm a cryptocurrency enthusiast by any means, but wouldn't prudent estate planning include a prepared will or some sort of next-of-kin document that includes a mechanism for access to your accounts/passwords/passphrases?
(And yes, that is a shortcoming of cash. Which is why we've invented other ways to store value, and approximately nobody stores their money in random holes on other people's property.)