And as for the why: I keep a small amount of Passworts physical at home or in my mind (like 5 or so). All others are in the password save and always random pass phrases. I also separate password files by purpose e.g. business, customers , private etc. I think that’s a same thing to do to keep accounts save.
Yes I agree, the best thing is to have a few password only in the head (complicated to withstand brute froce attacks, but simple enough to not be forgotten) which then can be used to open a vault to access the generated passwords.