The way I see it, Password managers protect best against website password leaks.

By making it very easy to have different passwords for everything, one password leak won't compromise your entire online portfolio.

The self managed nature of keypass and vault warden makes them less susceptible to a major fup outside your control, i.e A business can't mismanage your passwords resulting in a major leak or deletion. For better or worse, you're in charge of your own database.

They won't protect you from various malware, except maybe a key logger that doesnt know how to copy the file? If someone actually wanted into your database without brute force, they could figure it out. If you find malware that's been on your system for a while (longer than you download something and AV stops it before running), change all your passwords. Luckily you'll have a handy list of everything.

Edit; another advantage is if they take over the computer/steal files there's not much they can do with an encrypted password file, its better than a txt doc with all your stuff.