I may very well be using the wrong terms here, but then this is a subject I need help with.

I'm creating a space opera setting and I was wondering how to handle money in it. A lot of sci-fi settings just seem to use electronic credits, but does keeping hard currency offer some benefit for a society? Maybe it's more stable or something?
I kind of want to have a solid currency, as it leaves me more free to have traditional robberies and treasures and such.