Also known as King Crabs, you can always find kids grilling them whole on a beach in Thailand and then picking them to bits, but here not so much. I can see why they’re not harvested commercially (for food) since they yield not a lot given the work that goes into it (about ½ to ¾ pint), but they certainly are delicious.
Once cooked, with a good pair of scissors the carapace can be split and the “filling” (I don’t know what it is) makes an awesome stock. The legs and tail can also be peeled back to get at the meat, mostly where the legs meet the body. The flesh is firm and a little stringy the way overcooked scallop is stringy. The flavor to me is like a crab with the briny scent of scallops.
Besides the novelty of eating them, they are truly wonder bugs. Unchanged for 500 million years, they can regrow lost limbs and their blood is used in medical research for the way they gel up around harmful bacteria. They even bleed the crabs and then set them free and they regenerate all their lost blood within a week. How cool is that.