I also got confused when he said seed phrase on a password manager. I never use password manager but what I know to them is they only store login credentials which is commonly email and password.

I keep my list of seed phrase on an encrypted file inside and USB drive and I rarely get to use it. I only use it when I have to add new seed phrase or login my wallet to a new device. It's never safe to keep your seed phrase to a device that is connected online. Hackers are more skilled now, even a simple website link can get you hacked. You never know when your computer or phone could get infected by virus or malware.