I was flying QR Business and while they did have dine on demand, during the beginning of the flight, the flight attendant going around the cabin for meal orders insisted that I order something even if I am not going to eat it during their "standard meal time" (this is the time where the most number of passengers would be eating).

She basically said "if you don't order now, your choice may be gone by the time you actually want to eat, we will keep it for you and only heat it when you ask us to do so".