Lately on my premium credit cards (Amex Platinum, Delta Reserve) I've been seeing a lot of promotion for their "Plan It" program, where you can split up your payment over multiple months. Chase Sapphire has a similar program. It is typically for a fixed fee, but they often promote $0 plans if you set one up within the next X weeks.
As a caveat, I would nearly never use this with a fee. (I suppose if I needed to cover an unexpected emergency and the fixed fee was lower than whatever other transaction costs I'd need to free up liquidity elsewhere, I'd consider it.)
Any downsides to using it when there is a promotional $0 fee? As it happened, there was a promotion right after I made a couple of large-ish furniture purchases, so I set one up. Instead of paying $3k or so in my next regular cc cycle, it's split up over 6 months for free. It seems to be the same logic for putting purchases you could buy with debit on a credit card -- if you can essentially borrow money for free, why wouldn't you?
I can't see any downsides other than 1) the psychological effect that might make you feel like you have buying power, so you spend more than you otherwise would [but one already has to get over this for cc purchases generally -- if you can handle it for 6 weeks, why not 6 months?] and 2) using a higher percentage of your credit as the planned amount is taken out of your available credit [but my limits are absurdly high, and I am not planning any major purchases where I need to have super high credit]
Am I missing anything?