Would you use a pressure washer to clean a stove or refrigerator? If you used one, would you be taking a chance on getting water in the wrong places?
Commercial stoves have fiberglass insulation, which gets wet and stays wet. I do not know what residential stoves have, I have not worked on those. I have cleaned commercial stoves. Not too difficult. Start by taking off knobs and sheet metal. Then lift off the grilles, range stars, burners, drip trays and oven parts. Scrape most parts, soak small parts, including fasteners. The drip trays can be pressure washed, but usually scrapping and soaking works better. I replace most fasteners, too much trouble getting grease out of the Phillip head screws. I have one customer that wants the range/grille cleaned yearly. I price the job T&M only. When I am satisfied, I stop cleaning and start assembly. There are no good chemicals that take off the grease, I use sodium hydroxide. Oven cleaner is used outside only, and really does not work very well. The only exception is if you can put parts in a plastic trash bag, then spray oven cleaner on the parts, seal the bag and leave it overnight. The trash bag seals in the oven cleaner chemicals.
Same insulation concern with refridgeration appliances. But those appliances use foam insulation.
Walk-ins are not bad with a pw. Do the floor and walls first. Scrape food first, then use s/s pads or green pads or rags. Depends on the finishes. Do the ceiling last. Use a wet vacuum for water control. Dump the waste water in the sink. Warm walk-ins stink some.