Yeah Baras have a very distinct sound. Besides, Grimmjow doesn't seem to like Baras, he likes to brute force the crap out of people. And I don't think I've seen any of the Arrancar fire a point blank Bara. Since it moves faster toward a target, that would defeat the purpose of firing it point blank. Cero would be much more useful, and Grimmjow loves to do things point blank unless he's in a pinch.