It's accepted to have temporary wives (under a religious marriage for a few days) as escorts in Islamic countries, but quietly. Once it hits the press, authorities often feel compelled to do something about it.
But Sugarbook doesn't even fall under the fig leaf of temporary wives, and the membership numbers are shocking for a small country.
Some other commenters asked what's the harm of Sugarbook or OF:
1) women have a limited window to start a family and have children. Disrupting that has a very high price for both individuals and society.
2) making relationships purely transactional
3) normalizing the above across the population.