Answer:
To make chocolates and other types of gourmet foods.
Apart from the well-known chocolate candy, the original truffle is an edible fungus that grows underground at the base of trees. It is a member of the genus Tuber and is used in savoury dishes. Truffles are extremely expensive to buy and are used sparingly in both domestic kitchens and restaurants.
Pigs are naturally able to sniff out truffles and are used in truffle-producing areas to locate the fungus; the drawback with pigs is it isn't easy to stop them eating the truffles without binding their snouts, which affects their sense of smell. Dogs are easier to control and are now widely used to hunt truffles. A truffle-dog is worth a small fortune in truffle-country.
Truffles occur naturally in parts of Europe such as France, Spain and Italy, and are cultivated in some countries such as the USA and Australia.
The candy is named after the fungus because there is some resemblance in appearance, though not at all in flavour. Because truffles are considered a luxurious delicacy, the name lends itself well to the delicious creamy chocolate truffle.