I once bought a commercial dishwasher. It cost twice as much used as a domestic dishwasher would have cost new, and I had to add a 220 outlet and run some new plumbing; but the kitchen in that house had no space for a normal dishwasher, so I had to be creative. I put the big machine on my back porch, just outside the kitchen door: it was ugly, loud, and absurdly fast. Once it came up to temperature, it could wash a tray of dishes in three minutes flat. Great for cleaning up after dinner parties. It was certainly a kind of luxury, in a brute-force way.