Insects as food is an interesting thing worldwide. Actually many non-marine/aquatic species tend to be sold as either a culturally acceptable thing (not as much here), freak show as you mention (Thailand) or as an expensive delicacy. Crickets in Taiwan are an old time favorite, they are found here still, often more easy to find people collecting them rather than selling them. cooked at home. But things such as ants, bee larva etc are quite an expensive treat. So places like better restaurants or weddings they are common place.
Snails are common as, strangely considering how dirty african land snails are and the diseases they pose. The marine species of snails are more common and perhaps cleaner.
Marine life seems far more suited to Taiwanese dishes. the stranger and rarer the better it seems. so if people are eating isopods, for example, they look more similar to land invertebrates, helps make the bridge towards the land based bugs as a logical source of food.