WebUSB is pretty useful for web-based POS. Scanner and printer integrations.

It's great for a lot of use cases. We use it to enable a cross platform device flashing tool. Much easier to build and distribute than native applications for all platforms we need to support. Serial is similarly useful for getting logs off of devices.

you know what is better? a upstream kernel driver

I think you don't understand the use case. Kernel drivers don't connect the USB device to the JavaScript in the web-app.

that whole sentence is disgusting

But why should web-based POS be better than dedicated devices?

That's the wrong comparison. We used to only have dedicated POS systems, now we have the option to run POS software on a general purpose computing device. The question is why should that POS software be a native app instead of a web app?

What is your problem with WebUSB? It is really cool actually. I like making things with micro controllers that work with the browser. For example I made a device that lets you login to websites with an NFC card. Without WebUSB it would have been impossible.

I used WebUSB to flash GrapheneOS to my Pixel. Super easy and really cool, but kind of crazy that it's possible.