This is not just an isolated incident, it's the whole trend of limiting capabilities in the name of security and that's what I was referring to.

However in this particular case, even the security argument doesn't hold, either I:

a) know that I want to use USB - in that case I'll switch browsers or download a native binary (even more unsafe), it's not that I'd decide that I no longer want to flash my smartphone

b) I don't understand what's happening but I follow arbitrary instructions anyway - WebUSB changes nothing.