I would 100% agree that it is mental, but it's hard to enforce "X% of attention or less was paid to the road".
I see some people on their hands-free phone, arguing and talking with their hands, wandering out of their lane.
On the flip side, I fall silent on the phone, tuning out of the conversation because something on the road had me on alert. e.g. "Sorry I missed the last 30 seconds because someone changed lanes into someone else and that someone squeezed into my lane.
It is low priority and is shelved if the road needs more attention.
I used to text a lot when it was legal, I'd hold the phone up just above the wheel. I paid it as much attention as I would to my speedometer when a cop was in line of sight. Felt safe to me. I tried texting with the phone in my lap and prefer not to do that. It was safer back then for me.
I wonder how a cop manages to fiddle with the laptop mounted on the console while driving. Is there special training? Can I get some of that action?