What is the use of cash?
In the game there seem to be 2 currencies. Overcharge and cash.
Overcharge seems to be used for pretty much everything but after reaching credits, I don't think I've seen an instance of using cash for anything.
So what is the use of cash?
Apparently it's only for buying clothing, as https://www.ign.com/wikis/sunset-overdrive/Currency says:
Money can be found in a variety of ways, but it only has one use: Buying clothing and outfits from Calista after you meet her following the A New Friend mission.