Wow! I'm guessing I'd have trouble fixing those on my table! I don't have a vise that small AND precise.
(didn't mean to make it rhyme, but it did!
I've got a couple little 1 inch insert vises. They were not expensive as vises go and they are really handy when machining small parts. I also use them to take a part from machine to machine without losing to much alignment. They're really good for round parts that need some secondary machining like cross drilling, tapping, and milling flats.
Sometimes you can flip the vise in the big vise, and only need to do one touch off to be back on your part if you planned well and thought it through.