Dovetail cutters, are, as you might guess from the name, mostly used to cut the male and female (pins and tails) parts of dovetail joints. This joint is enormously strong and often used for drawers, boxes, chests and other places where one wants to join the ends of two pieces of wood at a right angle. These joints can be through, that is the end grain is visible on both sides, or half-blind, where the pins do not extend all the way through the wood. It is also sometimes used to cut sliding dovetail joints, to keep a wide board from cupping or join the shelves to the sides of a book case, for example.
Dovetail through joints can be very beautiful when contrasting colours of wood are used. Have a look!
Depending on the size, dovetail bits from Sistemi Klein are either tungsten carbide tipped (TCT) or solid tungsten carbide (Solid TC).