well the fenders are plastic and will not hold up any abuse. I have seen what Az rock does to painted flairs/fenders. it does the same to none painted too, just cost less to replace.
Face it if you go off road much or do trails for a Rubicon capable jeep, the paint will be first to go....along with any and ALL plastic including the plastic plate holder that hangs out.
So for many it is why pay to have them paint something you will be tossing away? My hard top I have not used in over a year, doorless topless. If the weather is bad enough I have soft half cab and soft doors.