Perhaps a lifetime of watching my rear view mirror, scanning traffic up far ahead, keeping an eye on drivers next to me, etc, has made those tasks mechanically low-effort. I find them more engaging than exhausting.

However, on long road trips, autopilot definitely reduces fatigue for me far more than standard cruise. I'm hoping now that FSD is on interstates, it'll be even better. (Assuming they've fixed the issue where the new minimum speed signs in my area are being read as a speed limit).