Going back to real world locks for a second - there are only so many potential key shapes in existence. Sure, a burglar could use lockpicking tools, but one way of breaking into houses is to try as many variants of the key as you have available.
And if they don’t work on the first target’s condo, maybe they’ll work on one of the neighbors’.
In encryption, a brute force attack sees an attacker trying out as many keys or passwords as they can in the hope of opening the virtual door to your secrets. This is one of the reasons you absolutely must use high-level encryption when each lock and key shape is unique.
And avoid all of the passwords on this list.