The last two hospitals I worked for had color coding (in PA and NC respectively). I was there when the switch happened from "where whatever you want" to nurses being burgundy, aides grey, etc. I was hired into the hospital in NC with color coding. There it was nursing: royal blue, respiratory: black (which always made me think of black lung disease), aides: burgundy, med clerks: grey, etc.
Personally, I like it. I looked good in both colors (lol) and it made getting ready for work EXTRA simple. But mostly I loved making it easy to narrow down who the last "nurse" was that my patients talked to. Before the color coding it was, "the nurse was just in here and said x,y,z" and it could be a PITA trying to figure out who it was. After the switch it became, "Tell me what color they were wearing? Was it this color that I am wearing or something else?" - anyway, it helped.