Where to begin?
1. I want drivers to install locally, not a requirement that I be able to go online to get them. What if the computer the device is connect to is itself unable to get on the web? You know, like that USB Gigabit LAN dongle I want to use to bypass the broken one on the laptop needs to have drivers BEFORE I can get online.
2. I like to have my anti virus & anti malware programs scan the drivers before I install them, just to make sure nobody has pulled a fast one with a bit of unauthorized jiggery pokery. I can't DO that if the only place to get the driver is online AFTER I've connected the device the drivers are for. How am I supposed to make sure you're not ramming some pile of shit down my computer's throat?
3. What if I don't WANT the device to be able to phone home, go online, or otherwise communicate with anything other than the computer to which it's attached? If I buy a temperature sensor that allows me to find out what my CPU is currently idling at, I don't want nor need it to go online just to find drivers, talk to some cloudy service, & spaf lord knows what information to whom.
You may CLAIM the device will only be able to communicate to a specific server & download specific software, but unless *I* say it can go online at all, then how the fek do you propose I get the drivers for it? How about you include them to begin with, & then let US update them later online if WE choose to do so? Better is if we can visit the manufacturer's site, find the device drivers, download a copy, & take it from the online connected machine to the one where the device is located, to apply said driver *offline*.
Your WebUSB api is a nice concept, it certainly would make it easier for you to make sure the device software is current, but it's an absolute security nightmare for the rest of us. I want control of where, when, & *IF* my devices connect to the internet, and want to make *damn* sure that they're not opening security holes through my defenses that'll send all my data to some scumball.
Can you ensure my privacy & security? Because if not then I'll not be connecting your device to my computer.