In fairness, lots of Protestant churches have very plain furnishings as a direct reaction to this kind of opulence. Personally I’m torn. Cathedrals are beautiful to visit, but I don’t think I could ever actually attend somewhere that imposing without being constantly distracted by it. Now some Evangelicals have gone full-circle with megachurches that are even worse…
I respect that. After all, different denominations are still relevant for a reason :). And there is Biblical precedent for a fancy building (Solomon’s Temple).