Web Bluetooth and Web USB, along with other useless things like Web Battery that Google loves don't make the web more powerful. It only serves to make the web more bloated and user hostile. And making new browsers that much harder to implement while taking the time of existing competitors.

As a user I have never needed or wanted web bluetooth or web usb, and I have never seen a person in real life that uses these either. For all I know, it's just mythical users mentioned in HN comments that want those.