There's always a single point of failure, if you increase the way you backup, it will increase your chance to access your address, at the same time it will increase the risk of getting compromised.
I don't want to make it complicated, I back up my seed phrase wihout the passphrase in many places, I only need to remember the passphrase, it just one word.
Some people are taking the concept of self-custody too far. Ordinarily, having a secure wallet where only you control your private keys is enough. However, some individuals are so cautious that they are unwilling to pass on their self-custodied Bitcoins to even their heirs, regardless of whether they trust them or not, maybe going to the grave with the keys is enough. We must understand that there are certain things we cannot control, such as natural disasters and even death. For this reason, it is essential to educate ourselves on best practices and use secure tools too.
Some people might even think storing in centralized exchanges is safer because if they lost everything, they might still able to recover using their identity. If their identity got burned by fire, they can recover it by asking a new one from the government.