system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why are complex passwords needed if you are locked out after three tries?
gpt
Here's something else to consider:

You're only locked out if you're trying your password on the live application, but there's no concept of being "locked out" if someone manages to dump a copy of the database where your password resides.

If an attacker manages to do that, they can try as many times as they want, as fast as they want, to crack your password, and it's under this circumstance that a cryptographically complex password will help save you.