*CONFORMAL COATING* is what we use to protect printed circuit boards from harsh environment such as salt water or extreme high humidity or corrosive environments, which the average home and hamshack does not ever see...
In the older equipment it was called MFP (Moisture and Fungus Proofing). Made a lot of old military gear
a real adventure to work on.
But don't worry about a bit of copper. Many of the older circuit boards didn't have any cover over the
copper traces and they still work 20 to 30 years later.