[fulafel]

They are not useless: they record when git used its fallible automatic merging logic to reconcile changes in two different branches. It works most of the time, but you really want to keep a record of it for later troubleshooting.

Have a look at https://github.com/git/git/blob/master/Documentation/merge-s... to get some idea what is going on behind the scenes in automatic merges.

[derimagia]

git rebase gives that just fine, even demonstrated here: https://git-scm.com/blog/2010/03/08/rerere.html.