@marsxyz
Mainly transparency. It makes it clear which behavior is okay and which isn't - but without the fuzziness and subjectivity of formulations such as "be excellent to each other" that can be interpreted either way.

Also, it defines clear processes for handling some situations. So the people who e.g. want to report something already know what they can expect.

Lastly, it allows to hold organisators/deciders accountable to their own rules.