i never trust those "90/180 days same as cash" type of flex pay plans offered at the point of sale, because too many have fine print for retroactive interest on the entire amount "borrowed" at purchase if you're even short a cent at 11:59pm on the payoff date. and naturally, they play games, taking like ~4 business days to process payments which is always like ~1 week around the holidays.

i know not all do, but enough do and i don't like being actively sold more than one thing at the same time (1) the actual doohickey, and (2) the one time financial product to borrow the money for the doohickey. with the CC, i have generally looked through the terms of using the card with a critical eye to find those landmines and plan how i will avoid them before opening the account.