NAGA probably likes to jump in and cut out their competitors. Even though they wont have the same turnout as normal, every competitor they take that would go to USGrappling if NAGA wasn't in town is a win for them. They had a NAGA on the same day as an IBJJF 2 years ago.
Honestly, NAGA is the place to go that day if you are a points player or want a belt with less competition than normal.
I know I'll be at USGrappling that day if i compete at all.