What do I want? It sure seems to do exactly what I need in the case where I'm on my local `master` and it's exactly the state of `origin/master` but a day or two behind.
What is it you're doing on your local master? It's only going to lead to a mess if you're developing on master locally and trying to do merges from upstream.
Absolutely no development. I use it as my starting point for feature branches, as well as subsequent rebases and merges on them. And I use it to build and run the current master.