I'm a bit surprised at the cost, which may or may not be good value compared to the cost of a kennel/cat house(?) depending on the duration.
There's a million reasons why one would travel with a pet but one of the more common ones would be a holiday/trip away. The pet owners would also need to carefully consider land travel arrangements. Pets are banned from hire cars and would require forward planning for taxis/uber. Similarly, accommodation would also require careful selection.
Who's going to be the first to report being on a flight with a pet? If pets are in Row 18 and beyond, most here won't even notice there's one on board (anti-social/disruptive behaviour excluded), until they venture from Rows 3-5 down to the back loos.