>Sadly, someone else will and weaponize it in an uncontrollable manner.

Except it isn't "uncontrollable". You have to explicitly allow every single website to use WebUSB. Without that explicit allowance, the website can't access anything.

Plenty of things can be weaponized, even household utensils. Should we ban all forks?

The sky is not falling, and WebUSB is not going to cause it to fall.