I feel like when you glorify gatekeeping piracy like oink or apparently what.cd had, you've lost the plot.
Piracy is largely a response to arbitrary rules in media distribution, like how, where, when or even if you can buy something. Hiding piracy behind a "textbook-length list of rules" is bad just as the system it is responding to.
No, it was a much better system.
Like all piracy, it didn't condition access on payment. And like all P2P, more users (because free) meant more content available to everybody.
The rules weren't perfect, but they imposed order and organization and prevented harmful (for P2P networks) duplication and fragmentation. Like any society, the rules helped to provide a framework to solve a coordination problem in a hopefully-global-utility-maximizing way.
The result was a vibrant community cooperatively maintaining a virtual Library of Alexandria of music where library cards were cost free.