One of the tricky elements is to do with security. Your crypto currency is held in a digital wallet for which you have an access code. This is not something you want anyone finding easily so the tendency is to put the code in some obscure place for safety as happened in Australia recently with a fellow hiding his code in a shoe which finished up in trash and then at a local council tip. He offered money to the council to allow him to search the trash where it may possibly have been dumped. The council would not agree and as Bitcoins were at the peak, theoretically worth many thousands. he lost the lot.
Most of us are not planning to die anytime soon so I wonder how many wallets will never get opened by family members of the deceased who has, for security reasons, not put down the access code in any place likely to be found. Without the code you aint got nothing. And if your code is found by someone who you wouldn't like to find the code.... chances are you aint got nothing.