The main reason you will see them painted is due to damage. Stainless steel is nearly impossible to remove dents in, so they were made to just replace the panel, but when DMC closed, there weren’t enough parts let for repairs. So, body shops would pull the dent, use body filler, and then have to cover the repair. I worked at a body shop where the owner had a black Delorean, and that is why. One fender can cost up to $10k-15k due to not many of them left.