Alpha, Beta, and Gamma make the economy system very confusing, players now have two meeble balances instead of one. Considering Gamma's currency is currently the only currency that is worth anything, alpha and beta are now in the process of being abandoned. By deleting alpha and beta, we minimize confusion with new players having to choose between three towns worlds, and also help concentrate towns to one town world, making this new towns world fresh, exciting, and active. If we keep alpha and beta, these two worlds would eventually die out.
I think it would be beneficial for the server to have one economy instead of two, every transaction would be made easier and the server would be more like a true economy server.
If people are concerned with their towns being deleted, the introduction of Gamma essentially deleted your town already by swaying all incoming new players to it. Make a new town in gamma!