These events could have been used to mark times of worship and, most important, to control a calendar, and certainly convert the city of Petra, “a place of awe-inspiring crystallization of natural beauty and the unique artistic creation of the Nabataean will” into “a gift from their gods, shaped by the supernatural and holding a holy meaning”
This reasoning could also suggest that the Nabataeans were more complex than one would give credit. Furthermore, religious signifigance to the city of Petra would also make it a moral sin to attack it. Very interesting in general!