If you check
http://www.swarovskioptik.us/en_us/products/rifle-scope_z6-z6i_1-7-10x42/technical-data and other Swaro spec sheets, the don't claim any super high light transmission percentages. That sheet for a Z6 states 90% light transmission, while other Swarovski models just say >90% .
Light transmission percentage alone doesn't make for image quality. For example, who wants a brighter image if that image is low contrast and low resolution? A brighter blob, with little contrast and detail isn't a good image in much of anything.
Soldiers used to use atropine eye drops to dilate pupils. While we aren't nocturnal animals, human eyes aren't that bad and we don't need night vision goggles to go hunting.
I don't know a soul that wouldn't pick a Z6 Swaro against the rest, assuming the same price. They aren't the same price, though.
