Nobody can remember strong, different passwords for dozens of accounts — so people reuse the same one. A password manager solves this: it stores every password in an encrypted vault, fills them in automatically and generates new random passwords.
In a company it also simplifies team access: shared accounts are granted to groups, and when an employee leaves, access is revoked in one place. The manager's main account must be protected with MFA.
Example
Passwords for shared accounts move out of an Excel file and into a team folder in the password manager, with an access log.