As long as it is interest free it is ok for me. Credit cards are convenient. But if I had to pay ANY interest I would resort to other payment options. It's no wonder they keep bombarding with the "great" conditions of their payment deferrals. The irony is that I would give NO credit to anyone that really was willing to pay that outrageous interest (looks really desperate and incapable of repayment).
ABout the leased cars... if you can do it with a negligible interest rate or you can deduct it as a business expense that is a very different thing. If you did it because you were UNABLE to pay it upfront and instead opted to pay outrageous interest fees over a few years that is again a sign of walk to the path of bankruptcy, it's those ppl who I was referring to. Although the credit card thing looks much more critical to me.
I use credit cards only for their perks (cashback) and to prop up my credit score. Hate that game but it's unavoidable. Pay in full before due date.
Most of car lease "deals" are horrible and lots of people tend to overpay because they focus only on the monthly amount, allowing dealers to screw them on down-payment and interest. These days car sales in the US are tanking (cars as in "not SUVs or trucks") so with a little bit of effort I can get a sweet discount and/or inflated residual value, drive it for 3 years, and leave the manufacturer holding the bag on depreciation. And keep my bitcoins too.
I've been in the debt spiral too. Not a fun time. Some expensive lessons have been learned.