Attendance is important because theaters need butts in seats, not to watch movies. For all they care, you can bring air horns to the Paddington 2 screening. Increasingly, theaters need you to show up and buy snacks and beer, or they’re in serious trouble.
This is similar in my mind to the hotel and hospitality industry, if not one is there to experience it, then it goes as a loss. You will never get that night back, that room that went empty or that seat that no one sat in.