If you do have local changes, then you would need to git stash/stash --pop before/after that command. I use rebase to keep down on unneeded merges for the common case of having exactly one upstream and not merging several branches together.
I'll never understand this subset of the development community who is obsessed with saving a few keystrokes. It almost invariably comes at the cost of flexibility, and creates a set of developers who only know the abstraction.
That's entirely the issue with Git for me. From the point of view of a programmer this is basic; obfuscation even. I'd love to take advantage of less painful merging/branching etc, but I work with engineers with a completely different domain of expertise - code is a means to an end. 50% of them refuse to use Git, and only accept svn grudgingly.