Private keys do need to be stored securely, but if you have a lot of crypto assets I recommend using a cold wallet or paper wallet.
The goal, of course, is to avoid hackers who want to take your private key from your computer or from your flasdish.
However, if you have someone who is truly trustworthy, you can provide the phrase or private key in certain circumstances, for example when we are sick, then we cannot exchange crypto coins and need someone we trust to be able to make these transactions.