If you are buying anything close to the cost of these speakers, you probably have a dedicated audio room, so why would it matter what a subwoofer looked like? I’d probably have a stack of Rel’s if I had a larger audio room and the Rels would probably sound better than this single SF subwoofer at 1/2 the cost.
Some of the better speakers have black only enclosures or I have only seen them in black: Magic, Raidho, Borressen, and others.