You know why I like Diadem?

Have you ever played Final Fantasy XI?

There is an endgame session called Dynamis. In the days of old, You needed an Alliance to successfully complete Dynamis. Once all the necessary parts were completed (such as killing a certain enemy and/or obtaining a certain item to clear it), if you have time remaining, the group stay in a certain spot and farm the rest of the mobs for Relic gear until time ran out.

Because it was Dynamis, Relic gear had some BiS pieces, and some pieces made other players envious of you. Diadem feels like the ending portion of Dynamis, which is why I like it.