Although I'm a heavy Emacs user, I never understood why is magit so praised. IMHO, source control just doesn't belong to IDE. Why learn how to use git with Emacs/magit, vim, IntelliJ IDEA, Eclipse, Visual Studio / Code, ... when you can just master the official command line client and forget about the rest? It's available and usable everywhere, while each of these IDE plugins is different and one need to learn and ge…
If make multiple edits to different files before committing, this can be very useful to ensure that the commit makes sense, doesn't include logically unrelated changes, and so on. Or, if you follow a "commit early, commit often" approach, Magit's interface is also nice for restructuring those commits during a rebase/squash.
Perhaps it helps to think of commits as documents in their own right, as commits are effectively patch files, at which point it makes sense to use an editor to, well, edit them.