Invariably people who use that service plan to spend 100% of their monthly income. Whenever you have an unexpected expense in that 12 month time frame and have to pay for that, then you can't make the payment on that loan.
Yup, debt is purposely setting you up to put you in exactly that bind, and then you owe the serious interest. Kind of a reverse lottery where you lose. It doesn't happen to everyone, but at scale, Life Happens, and a certain percentage of people will get behind and wind up paying huge interest, and there's the profit model.
Also, people are chronically up in arms about taxes, but here, they are signing up for voluntary taxes on everything. At least taxes buy something real, like roads, mostly reliably safe food supply, education, police, fire defense, etc., while interest just buys indulgence today then headaches tomorrow.
Interest is fine if you are creating an asset that create greater future value (e.g., building a business), or where the asset itself is a security (e.g., a house). But for transitory consumption, debt is a losing game. (I'm distinguishing debt from credit cards as a payment convenience paid every month - don't let them slide)
Hate to throw a variable into it, but I usually spend less than 50% of my income (after savings and retirment), and I still use BNPL and payment plans when I can get interest rates and fees for under 10%.
