Although I don't know a lot about this, isn't the catch that if you don't pay in full by the end of the 0% period they go back and charge interest on all the months you didn't pay?
I really don't understand credit cards well. I have one but I pay the balance in full every month so I've never had to figure out how the interest thing works. When I worked in Apple Sales (I was a salesperson for the Apple Store Online by both phone and chat via Arise as an independent contractor), there was no good training on the two credit options. One was called something like Buy Now, Pay Later, and the other was the Juniper credit card--it might be Barclays now. None of my PFs (performance facilitators) could explain to me how it worked either. I would always sigh relief when people weren't approved because it seemed to me they didn't understand how the credit worked either and many were not in a position to be buying. To be clear, I wasn't taking credit applications--no one at Apple does that as far as I know--I would give information about the credit programs and direct people to Juniper, etc., or tell them where the online application was. Everyone thought of the Juniper credit card as a payment plan, and I would always try to explain that it was a regular credit card but with this promotional offer. I think people thought it meant they would pay a little at a time, not realizing there would be a huge interest hit later on. It was a bad situation in that I actively sought out more training on the subjects but was basically told it wasn't our responsibility to do anything more than give out the phone number or link.
I never saw anyone approved.