I still don't really understand why so many devs seem to have a need for this. For me every commit I make is a good one that I would like to keep in the history. Why should I need to reorder or rename or group any of my commits? All my work (of days or even weeks) is neatly containted within one branch, and that branch gets merged at the end. Why is that not ok? Why should I hide my work history into one "blob" commit instead of just having the Merge commit on the master branch?

The only use I could imagine is, if you have very short-lived branches (i.e. 1-2 days) with lots of random commits. Like e.g. "Oh I'm going for lunch, lets commit."