If ever someone dies and their family member or spouse never knew about bitcoin, your coins will be gone forever it is just like losing the key of your unbreakable safe. That is why to prevent this you need to put write it with paper and specifically put that you should not throw this away because this is money and also make sure that you put the amount of the money. If they see that they will never throw it and it is really up to them if they want to learn on how to use bitcoin and cash it out or continue investing it.