It shakes the dirty off in a liquid using ultrasonics.

Are they suggesting they do it dry? It is unlikely that works. It is far more likely they have a strong vacuum doing the work and maybe… maybe they have an ultrasonic actuator supposedly shaking the blinds. But there is so much variation in blinds it is unlike the frequency they are using is at the resonant point of the blind where it might actually do something.
Some camera lenses and mirrors on high end cameras self clean using ultrasonics. But the frequency and amplitude has been carefully chosen to work on that particular part. Move it to something else and it will not work.
If you do let them clean your blinds make sure they have a HEPA filter on their vacuum.

I’m with @Tropical_Willie. The cleaning process works like this. It “uses vibrating sound waves and tap water to safely remove dirt, makeup and body oil from your favorite jewelry (gold, silver, platinum and diamonds) and metal watch bands. Simply add water and place your jewelry in the holder. Ultrasonic vibrations loosen and shake off dirt and residue. Within minutes, your rings, bracelets, necklaces and other fine pieces are restored to their original showcase luster. You may also add a drop of dish soap with degreasing agent. For oxides and other tough stains, add a Sparkle Pak (sold separately).“
https://www.sharperimage.com/si/view/product/Ultrasonic+Jewelry+Cleaner/200626?utm_source=Bing&utm_medium=CPC&utm_campaign=Cleaning&Keyword=Ultrasonic%20Jewelry%20Cleaner&device=t&creative=9309663967&cm_mmc=CPC-bingCleaning_-Ultrasonic%20Jewelry%20Cleaner&mkwid=0ac8Hr7N%7Cpkw%7CUltrasonic%20Jewelry%20Cleaner%7Cpcrid%7C9309663967%7Cpmt%7Cbe%7Cpdv%7Ct%7C&msclkid=cbd668db99341df25c4c323e0f42a902

Ah, yes, @snowberry, I can understand how it might work with jewelry, or even dentures and dental “night guards”. But window blinds?

@2davidc8 The cleaning process is the same, whether it’s jewlery or window blinds. It’s a handy way to clean anything without needing to manually scrub it down. And it’s very fast. Time is money, as they say.

I have professionally cleaned window blinds, and I’ve always done a great job, but it’s kind of boring and definitely time consuming.

@snowberry With window blinds, do you just kind of run a wand over the blinds? I’m having trouble visualizing the process.

@2davidc8 blinds can be dusted that way (its best to use a brush attachment with a vacuum cleaner), but some people try to wash them in place using a wet soapy rag. If it’s really dirty and there’s no other option, it’s better than nothing, but it turns the strings black with the dirt you had just washed off of the blinds.

To remove food, grease, or smoke residue, you have to take them down and immerse them in a long low waterproof tray with soapy water in it. I’ve always used a bathtub, but blind cleaning companies have a more convenient setup. Here’s a link for the various ways you can clean blinds. The link below says you can clean them hands free if you turn on the jets in a jetted tub. That method would work a bit like a dishwasher would, but I can’t see how it would clean them if they’re lying close together (which of course they naturally would). . However, since ultrasonic is known to clean jewelry, it would also do a good job on blinds- as long as they’re completely covered with the cleaning solution.
https://www.onegoodthingbyjillee.com/2014/10/clean-window-blinds.html

This blind cleaning company makes some good points as well. Ultrasonic cleaning makes it possible to clean fabric (honeycomb shades, etc.) with no wear to the fabric. Slick!
http://www.dirtyblinds.com/blindcleaners/intro.html

Great, @snowberry, thanks for your detailed answer! And thanks for the links!