He acknowledges you can do that with a well-sharpened knife. Of course you can do it with a well-sharpened knife. It's exactly the demo every single sharp knife does! His claim is that the ultrasonic knife will always do that cut, whether or not you assiduously keep it sharp, which is what I have to do with my MAC and Yuki to make it cut tomatoes like that.

But most chef-knife cutting isn't thin tomato slices, and you can always do that cut with a good thin serrated bread knife, too. I want to see it dice an onion. Seems like a small ask.

Yep, I have a Shun with micro serrations ([0]) that will slice a tomato so finely you basically feel no resistance.

The only downside is that you can’t really hone or sharpen it yourself so you have to baby it. I’ve had mine about 15 years and have sent it in one time for their free sharpening at about the 11 year mark. At least Shun blades hold their edge a really long time.

[0]: https://shun.kaiusa.com/classic-serrated-utility-6.html?srsl...