What is the usecase for WebUSB? Here [1] someone from Google suggests vendors should write device drivers in Chrome HTML and Chrome Javascript. Please don't.
Or (my assuption) it might be for devices that cannot work without browser and network connection.
Yeah, the great thing about WebUSB is that it can easily be used to upgrade devices to new firmware with new features. For example, suppose that some end user's USB device lacks the ability to act like a USB Rubber Ducky and inject malicious keystrokes in order to compromise their machine. WebUSB allows a clean, easy way to fix that remotely.
Next step will be devices that cannot work without Chrome, network connection and "anonymous" "telemetry" for the purpose of "improving customer experience".