“Seat time” is literally what you are giving them in that situation. You can say that it’s not “time” but I can say that it is because there is nuance and we are doing many things at same time. Being present physically, mentally, paying attention to your surroundings, putting in effort, etc, can in many ways be counted separately. Who’s to say if your way of accounting for time is the “correct” one or whether somebody else’s is?