A joker can be used to complete a set, for instance, if a player has three 8s but not an 8 of hearts to finish it. However, if a sequence can be finished without the usepte available slots of a joker, it might be better to save it for later rounds when it might be more useful. advantages of jokes in rummy. Jokers are extremely valuable in rummy because they can be used as replacements for any card. They can be used to finish sequences or sets, and they can even be used to make more than one combination out of one card.