The Chamber of Awakening is there. In 358/2 Days, Xemnas is looking for it, presumably to find Ven's armor. The room that Xemnas goes to below the Heartless Manufacture is the Room of Repose and Aqua's armor is down there, so I can only assume he's looking for Ven's armor, since Ven woke up in a room that looked like the Room of Repose, but with different floor markings.
If Vantias really was born there, than it strengthens the relationship between Vantias and Kairi/Namine/Xion, which is my current conspiracy theory.