Just like watering holes, mountain man rendezvous encampments, bus stops, food courts, midday corners in various cities around America, and skate parks: hot springs are a classic Public Gathering Nexus. However, unlike most PGNs, Hot Springs possess a gravity incommensurate with their intended use/design, because while many Hot Springs Enthusiasts come for the healing vibes and therapeutic water, just as many (if not more) come for the Hot Springs Enthusiasts themselves, a.k.a., The Scene.
A short list of non-healing-vibe or therapeutic-water-related reasons to visit a Hot Spring: To get naked in public. To be seen naked in public. To see other people naked in public. To sell marijuana and other drugs to people in various states of dress. To chill. In the pursuit of a captive audience. For warmth. To swim. To meet German dudes and literal busloads of Koreans. To steal underwear and shoes.