These hammers are special purpose tools for smithing. They should not get circulated with the rest of the hand tools. Ask Dan J before you borrow them for something else.
These are the bread and butter hammer of blacksmithing, your #1 tool.
Kinda like a very shallow ball peen. Useful for moving metal laterally, more agressively than a cross peen.
Useful for detail work that the Cross Peen is too aggressive/large for. Used for heading rivets, making leaves, texturing.