FSD does use the internal camera to enforce eyes on the road hands on the wheel. It’s actually worse for road-trips on the highway than plain autopilot for this reason, aside from the fact that FSD will automatically pass and change lanes.
I imagine a negging Tesla car would say something like "it's so cool to see a person who has so little to lose they don't care whether they live or die" when you take your eyes off road and/or hands off wheel.
My car came with an internal camera that didn’t have IR lights, which made FSD completely unusable at night time (they put in a new one under warranty).
I only subscribe FSD every few months for long trips, but I have a 1400 mile road trip planned this weekend and I will be using plain autopilot.