[nloomans]

These example commits seem like pretty bad commit messages to me. They are just a summery of the changes (something a motivated reader can rediscover by reading the diff), while leaving out the why, which will be lost to history if not documented.

[retSava]

Yes, the why is very very important, but imo it's also useful with a one-liner summary of the actual change.

Consider a trivial change but affecting tens of places in the code, eg an API change. It's very useful to be able to quickly glance past "use new abc-API; required since dependency X bumped to Y" and mentally move on, rather than actually having eyes scanning over those actual changes.