I don't have the memory bandwidth to memorize a hundred unique passwords. I memorize four or five passwords (my email, my bank, my work, my home and my password manager). For everything else (my Slashdot, my wifi, etc) I use a password manager. Given that most websites uses email password resets just remembering my email password means I can log into almost anywhere from anywhere with a network connection.
Yes, very few tools are stellar in every scenario. That's why I use the tool for the less-critical scenarios and remember the critical ones. Even if I were to forget my password manager password and lose access to my password manager permanently, I can recreate those 100 passwords given some time.