I tend to use gists as a sort of snippets library (of sorts). I always have bits of useful code that I am going to need again at some time and having something like a gist is quite handy.
Yes, personally I use a single "miscellaneous" repo for this purpose. Do you not find that, when working on one of those snippets, you want to commit your changes (in your present command line environment)? Copying and pasting into a web browser doesn't seem an attractive way to commit. I'd be interested to hear what your workflow is.