Of course it is a tradeoff between security and usability. Not putting your passwords online forces you to either remember all passwords (which will lead to re-use) or you will be only available to access your accounts (and thus most of the internet) from your home. Or you will have to come up with elaborate system how to carry your passwords on some kind of secured device etc. A password manager (alongside 2FA) is a very good security/usability compromise for a lot of people. YMMV.

The thing is that accounts get cracked because of reuse all the time. Whereas they seldom if at all get cracked because they’re in a password manager.