Although I did before they were commonplace, I couldn't imagine riding trails on my full-sus without a dropper post these days.
I'm sure at some point we'll see a road bike or two with a dropper, especially if you go with the AXS wireless version so no extra cabling needed. They'd be more useful / at home on a gravel type bike rather than a pure roadie though.
Unless somebody is looking to eek out every last drop of downhill aero speed without supertucking, I doubt the cost and weight penalty is worth it.