Women are always attracted to, even if they are behind the long tail, and neck powdered gills. About mermaids know from the times of ancient Greece, but it is usually not good for a person they do not carry. It was not until as long as there was not this slot Mermaid's Pearl.
Also in the underwater world of mermaids is something to see. It is flooded with sea delicacies and beautiful scaly fish. Shipwrecks brave diver can give a pleasant surprise, and so it would be - wet playing cards, a huge pirate chests of gold - a question to Lady Luck.
Good luck and pleasant pastime!