### OFF TOPIC OF OP BUT STILL IMPORTANT ###
The danger is normally that when one tries to remember all their passwords, they invariably end up using the same password in multiple locations. Otherwise, how would you remember which password was for which site? This is the most dangerous password practice there is as all it takes is to use your email/password combo on one infected site and they can access many of your other accounts (usually including your email itself).
If you can remember 500 unique passwords for every single site you’ve ever signed up for, more power to you! But for us mortals, encrypted password managers behind huge layers of security is infinitely better than storing your passwords in exploit ridden browsers that sync to everything they can find.