Earlier quoted context omitted.
There's a lot of good use-cases of Web usb, you can't just cut everything which might have privacy aspects otherwise the browsers wouldn't have canvas or even gpu rendering.
What are those use cases? It seems like a giant hole punched all the way from a tab's sandbox through the process boundary and out to the kernel... Yes, gpu rendering is a great example of the same problem. Canvas at least has some intervening layers depending on implementation.
I used something similar in the past. It was a legitimate use case for web usb which changed my mind on it quite a bit.
https://www.charachorder.com/ sells ergo keyboards and allows you to update their firmware directly in the website, through web usb. No local apps at all. Also an improvement in overall security from having to download some .exe / .dmg and running it locally.