To be clear, I'm not asking for SIP or any kind of special browser support for calls, just being able to "copy & paste" and dial a browser-displayed phone number for the existing BT-connected phone to dial.
Use case: from the parking lot today, I used the browser to find a Thai eatery. The number and address were displayed on the screen, but were useless as I had to go into my phone to load the same page anyway just to be able to tap the number to dial & tap the address for directions. I expected that tapping the phone number on the browser would DTRT, but alas it does not.