A sporran strap would buckle like a regular belt, but have hooks that snap on the rings on the back of the sporran. I would expect this is necesary to make the stap lie flat.

You COULD remove the little piece of leather and rings from loop on the back the sporran and just run a narrow belt through there, but I'm betting it would not hang right.

Of course, my answer does not take different sporran construction designs into account.