Moundbuilders' appeal seemed more novelty than anything, a sensation that wears off quickly on the less interesting "mound golf" holes. Considered in a vacuum, at least the Viking burial place at Cruden Bay seems a natural feature to construct a golf course around. Moundbuilders struck me as exagerrated mini-golf features, and had Bendelow built the mounding himself (rather than route around existing earthworks that had existed there for centuries), we'd be tutting and citing the Macdonald quote in my signature below. Hundreds years of separation does not naturalism make.
The claims that Moundbuilders CC saved the earthworks are probably accurate but let's not try to frame it as one of the founders' goals. It's not like Keisers-at-Sand Valley, where the founders saw the wonder and committed to preserving a chunk of it. Moundbuilders' founders saw landforms that would make for a curious course, not a monument.