A bingo game takes more than an hour to play and can provide more fun at a lower cost than the same time spent on blackjacks or craps.
Older people can play bingo to occupy their free without losing too much money.
I don't know where you seen a bingo game take more than an hour, they mostly take just a few minutes each. I used to have to go with my grandmother a few years back and she would be running 8 boards simultaneously and they read the letter/numbers off so fast I am not sure how they kept up. I always hated when she would go to the bathroom and I would have to watch her boards, as it was a lot to scan when they would be calling off B14, N3... in rapid succession and people yelling bingo all the time.
I also think they charged $1 per board/per game, so over an evening they could have a few hundred dollars wagered in an evening easily. Of course, the payouts were pretty good too, with usually a few hundred people playing at once, and I believe a 80% payout. So a couple wins could put you ahead for the night.