Yes, but git doesn't force you to do this -- you can be as messy as you like with git, knock yourself out. Git is NOT opinionated. I am opinionated. But Mercurial and others don't make it possible (or easy) to get nice, clean history, therefore they are inferior.
And no, "just diff between merges" is NOT nice and clean. It bundles lots of changes together, therefore you can't easily separate them without actually understanding all of it. The cognitive burden of reading diffs is high. The cognitive burden of reading commit subjects and messages is lower -- much much lower.
One really does have to be considerate of the people who will be maintaining one's code in the future. Even that will be you yourself, you should still be considerate to your future self.
When you work with codebases measured in Mloc or Gloc, you really need the code and its history to be accessible. This is obvious to people who have worked with such codebases. It's less obvious to people who haven't, but it it's still true.
And no, "just diff between merges" is NOT nice and clean. It bundles lots of changes together, therefore you can't easily separate them without actually understanding all of it. The cognitive burden of reading diffs is high. The cognitive burden of reading commit subjects and messages is lower -- much much lower.
One really does have to be considerate of the people who will be maintaining one's code in the future. Even that will be you yourself, you should still be considerate to your future self.
When you work with codebases measured in Mloc or Gloc, you really need the code and its history to be accessible. This is obvious to people who have worked with such codebases. It's less obvious to people who haven't, but it it's still true.