If you limit exchanges to only those with reciprocal supply & demand then it becomes much less less likely to identify deals where people can use the service to

If you limit exchanges to only those with reciprocal supply & demand then it becomes much less less likely to identify deals where people can use the service to provide value for each other. Assuming there are n different kinds of expert services, and each participant supplies one service and demands one service at random, then there is only a 1/n^2 probability that an arbitrary participant is able to enter into a reciprocal trade with you. If you instead use some kind of credit system where providing service to participant X gives you credit that can be traded in later to obtain service from Y then suddenly each participant in market has 1/n of being able to reach deal with you. So by reinventing something that sounds suspiciously like money by allowing trading of debt/obligations for services we have made our expert network much more efficient at being able to identify and unlock productive economic exchanges between people.