Most common reason is she rather her future customer be repeats with a decent customers rather than unknown ones. If you paid, maybe even tipped, and was pleasant to work with then she rather you be her future customer than take a chance on someone unknown. Maybe a new guy doesn't pay, he stinks, too much demands, etc. So connecting on social media/communication keeps the channels kind of builds a pipeline of good repeating customers.
I'm sure there are girls that wants to connect with you just for the purpose of working you and getting extra money beyond a simple punting transaction, but personally haven't encountered that (maybe because I'm not a huge tipper
) . I'd say most girls I've connected more or less never even bother messaging me. Except sometimes they tell me when they're back in HK.
