Buying expensive things gets really difficult. With valued currency, you can simply save and spend it all together to give it enough value to something big like a car or a house. But buying a car or a house today on a bartering system would be near impossible- what could you even trade them for something like that?
Someone might not want anything you have. Example, you only have an apple but you want a orange and someone has an orange but they dont want your apple.
