Talking with an Etsy jeweler who said when they are both the same metal they have a tendency to polish each other. Intriging.

hmmm...that has not been my experience. But again, it doesn't bother me other than thinking eventually the bands will thin?

That's what I've seen with my palladium set. At least they wear evenly and at the same rate, as opposed to two different metals, so I notice it less

With Pd, you won't lose metal either, so any scratching/patina can be buffed out.