It doesn't seem to be the sort of thing that even has a chance of being profitable... The only reason to join is to save money on tickets, the only way they make money is if people spend more on membership fees than the tickets they buy.
I could easily imagine myself signing up for a service like this and then forgetting about it for a month or two at a time.
I still have it, but I consider it an aspirational purchase for a time when I can actually go to movies. I think I'm averaging about 2 movies for every 3 months.