That analogy is desperately tortured. It just ... does not map at all to how I ever perceived reading or fun videos. I never even heard anyone talk about it is those terms.

The time spend by purely relaxing activities like reading or watching is on itself a reward. You do it instead of doing something less pleasant- staring bored at the wall.

And the idea that you could have spent all that time doing something super useful is wrong if it is about opportunity cost. I tried multiple times to cut off all "time wasters" like reading fiction or videos. It ended in low productivity and depression each time.