Except no one cracks passwords. Vast majority of hacks is through social networking and trojans. The days of password cracking are long over especially considering most services lock you out after several failed attempts.

The main argument for using a password manager is so you can have a different password for every service. This way if they manage to obtain one password they can’t access everything.

It also makes rotating passwords a lot easier so that way you’re not using the same password forever. If your password gets out hopefully it’s changed before they use it.