1. Waste of code reviewers' time

2. Waste of later coders' time when running git blame on a line when trying to figure out the purpose of code

3. Waste of later debuggers' time when they need to decide whether this error is the thing they're looking for, an unrelated error to bisect skip, or an unrelated error in possibly-related code that they need to manually fix and then re-test.

As the other sibling poster says, it's about not wasting other people's time. Make the messages/descriptions ruthlessly short and to the point and your colleagues will like you.