[FuzzieAlum]

Couple of reasons.

1) If a local joins a national, how else can the members be initiated?

2) If someone transfers campuses, she may still wish to be a part of a sisterhood, and obviously there won't be a chapter of her local there.

3) Some locals (by no means all or even the majority) are groups that start and falter fast (I'm talking months) - the women don't really experience sorority life or sisterhood at all. Technically, they are maybe full members, but in reality their experience is more akin to a pledge period.

On many campuses, the local Panhellenic forbids women to join both a local and an NPC (basically, the local is treated as if it were an NPC member). Personally, I think more campuses should have this.