These aren't mutually exclusive things. Write readable code so people can see how you did it. Write complete commit messages so that people understand why you did it. Especially with older codebase, hairier things you inherit that are full of monsters and WTFs, you need both.

It's more work for you, but it saves the rest of the team even more time. It helps the dev reading it in three years understand, when he git blames to figure out why you did this strange thing.