Nope, this is no existential question (although...). Everybody's talking about "When will Bitcoin die", but what if you die, and your family don't find your key, or don't understand it, or think it's only a useless sheet of paper with some code on it, or simply throw it away... Does this mean the currency's gone forever?
I find the possibility of this event rather realistic (yup I don't believe in eternal life), so that means that someday there might be 21M BTC but only 18M (and counting down...) is left in the market?
If you didn't tell your family about the bitcoin investment, then it will become useless after your death. You must share about bitcoin and its password to a trustable person. Then only they can use that after your death. So please disclose it to anyone who is more sincere to you and trustable to you.