Why does the US no longer use the barter system as its economic system?

Bartering only works when each party has something that the other wants. For example if I own a printshop and a dog, then I might find a groomer who needs printing (perhaps some forms or business cards, for example). The printshop owner could offer printing some cards for getting the dog groomed. But what happens if it is time for the dog to be groomed again, but the groomer is not ready to order some more cards. The need/want is only on one side of the transaction, so the barter will not happen in this case. There are barter groups or clubs that will assist with finding suitable transactions. See the article in the related link, below.