Well of course. That's like saying you can't make toast in the kettle, but it doesn't stop the kettle being useful

Microwaves are incredibly useful if you can do anything besides 100% power.

Microwaves, or microwave ovens? Because I can name all sorts of ways that microwaves have improved communications. So many long-haul telco links, and remote radio/TV stations, have been accomplished by microwave. It's a powerful method of transmission.

Unless you're specifically meaning microwave ovens, which are of "limited utility" in a full-service kitchen. I'd have to agree there.

My previous microwave oven was so intensely powerful, that I needed to dial down the power to "7/10" so that it would not destroy my frozen meals. I could never run it at 10/10. My current appliance is very nice, and has an automatic button to run until doneness. Works every time now.

What's your point? What doesn't have limited utility?