I think it is a very good thing you bring this to the attention of all of us. I have been looking at cryptocurrencies since a couple of months and this week I decided to collect all my login stuff in one place (Keepass), and put it on a usb drive so it is offline. the usb drive is then encrypted with windows bitlocker. I made a backup of the drive and gave it to my parents. Whom I trust. The password to the drive and to the keepass file are public but they will have to look for it. I told them where to find it but it still will remain a puzzle i know they can solve. In this way, if anything ever happens to me, they can get into my my accounts and retrieve what is theirs.
However, you do mention a valid point I had never ever had to worry about. Is your relation with whomever you would like to give the backup to, trustworthy. I have no answer to this. This is, in my failsafe strategy, the weakest link.
Thank you very much for your comment! I am afraid, as long as we are humans, this is going to stay the weakest link and there is maybe no cure for that.