The people who get their coffee to go and the ones who sit at the tables are different segments (although there is some overlap).
Also, the sitting customers can be segmented as well: most of them will sit down for 15-30 minutes and leave, but there are some who will stay longer. It would be difficult for someway staying 4 hours to spend as much as 8 people staying 30 minutes each, so that's why djt talks about the need to turn over tables.
I 100% agree with you. I was questioning jmduke's assertion that 4 hour sit down customers are more lucrative. As I see it, they are the least lucrative customer.
Also, the sitting customers can be segmented as well: most of them will sit down for 15-30 minutes and leave, but there are some who will stay longer. It would be difficult for someway staying 4 hours to spend as much as 8 people staying 30 minutes each, so that's why djt talks about the need to turn over tables.