The rules are the case because they want new/low pop servers to have players so they lock them there (but they are very clear about this).

You can still raid on there if that's your intention (just DC travel to Light) but be aware they do it differently. They use fixed positions for each role with macro positions like JP does, so for example OT is always in same spot, Melee DPS #1 is always in same spot, etc.

You can meet NA friends by traveling to Materia but the ping for everyone there likely won't be good.