hotpot started as poor people food (throw whatever you've got handy - the stuff nobody else wants to eat - into intensely spicy oil broth), then rich people caught on and the "weird" exotic stuff became expensive delicacies

Same thing happened in the west with stuff like oyster and lobster, it was the garbage food that the fishers would eat after selling all the quality food (fish) and then rich people came along and were tricked into eating the leftover snot balls and sea bugs and they become fancy expensive rich people food.