I always assumed that pay for hours outside of regular working hours would be higher than regular pay.
Otherwise life as normal. Laptop in the car, 4g hotspot on my phone. Only actually had to fix an issue remotely a few times (once with only my phone in a restaurant after a martial arts class).
https://physiciansthrive.com/physician-compensation/on-call-...
Yes, you cannot go on a hike, which is why you get paid. You don't get paid more than you do for your normal time working though.
So they are paid for being available at a diminished rate, and if their availability is needed, then they are paid overtime.