Quite often, many servers call ranks "Donations." The idea is this for premium: If you pay us money, you help out our server a lot! We will love you forever. Have these perks.
That was a gross over simplification. I understand that premiums are what make Aloria go round. I would say that, just to be safe, you guys should ask Marc before assuming anything. But the idea of premium is an incentive to help the server to most people. I would love premium myself, but I got no moniez! The money goes to fund the server, but it is still money for an in-game feature. You can call it a gift, and it is, but so is a rank. You pay 10 dollars to donate, but you also vet the rank of VIP and the ability to use diamond stuff. That is not only selling an in game feature, but selling a rank from a plugin which is protected under Mojang's ownership. Mods or plugins is still selling something for their game. Just like, for example, if someone makes DLC for Smash Bros. and charges $10 for it, that is illegal. It is making money using someone else's code. The plugins operate with some of the basics of the Minecraft code. Like entering commands, tools, blocks, etc.