The BB card is generally easier to get approved for compared to other extended 0% cards, such as Simplicity / Slate, so that might be a reason why he's going for the BB card. Like others mentioned, there's also some discounts and promos as well.
From a rewards standpoint, 5-6% discount for using a BB card is nice too, especially now that the $2000 cap has been implemented for the Cash+
JPMorgan Palladium (100k), AmEx Platinum (NPSL), AmEx SPG (46k), AmEx BCP (42k), Chase Sapphire Preferred (47k), Citi Prestige (31k), Citi Thank You Preferred (27k), Citi Executive AAdvantage (25k), JPMorgan Ritz-Carlton (21k), Merrill+ (15k), US Bank Cash+ (22.5k), Wells Fargo (12k), Bloomingdale’s (12.4k), Chase Freedom (5k), Discover IT (5k).
