or you can use slightly thicker copper. but sometimes you can’t, and that’s when silver is a slight upgrade

i heard that microwave parts for satellite use are made this way: first you start with aluminum, for structural and weight reasons. then it’s plated on inside (where microwaves are) with thin layer of zinc, then with copper. you can’t plate copper on aluminum directly. copper is there to conduct microwave current, but silver is even better, so there’s a layer of silver to conduct most of it, and copper handles the rest. then it’s topped with gold, but it’s a very thin layer, so thin that it doesn’t conduct a lot of current. it’s there only for corrosion resistance