Ben,
Using the Wedgies as the example:
As I understand it, since the Wedgies have a natural roll off at 200Hz, frequencies below 80Hz would not be heard even if a full range signal is sent to them. However, just because you can't hear those frequencies, the drivers still have to deal with them.
By filtering out the frequencies below 80Hz the drivers don't have to deal with the energy associated with these frequencies. By not having to deal with this low frequency energy, the drivers can handle more power for the frequencies they can reproduce. This means they can play louder and cleaner.
So while the filters (whether inline or EQ'd) are not necessary, using them allows the speakers to perform at their best.
Mike