Maybe for the CityWalk merch stalls, but anime/manga merch is only sold in MIB Gear (not counting airbrush hats/tees in Custom Gear, the CityWalk stand, or the claw machines in Kingpin's and Palace) and I haven't really noticed an increase in the amount of retail space it occupies.
Does this includes HHN merch? It would be incredibly surprising if UCM outsells stuff like Jurassic, Marvel, Minions, Simpsons, and Spongebob.