I personally believe it makes it much more fair for everyone. It's the first server I've ever been on in which /pay is disabled, and it makes it more rewarding when you earn the money and rank up by yourself, rather than having someone just give you the money- otherwise, what's the point of playing?
And in terms of trading with other players, using mana to buy things is a great idea, and from my experiences, makes ManaCube very original.