That's cool for you, but I'd guess less than 1% of folks in the US have ever paid full-price for a phone just to say "I'm not paying monthly towards this debt".Debt is debt, call it what you like. If I don't have the money to buy a new phone outright, I don't buy it.
The main debt vehicle for new phones (until a year or two ago) was the 2-year contract. You could buy a $649+ phone for $199 down. Part of your monthly payment went towards paying the remaining debt off. And that was the rub... after you paid the debt off, your monthly payments never went down. So you continue to pay, as if you had a debt, even when you had none. So in that regards, it made no sense to ever pay full-price for a phone.
Now you can buy a $649 iPhone for $0 down, and then pay monthly until the remaining debt is paid off.
Not much different, IMO. At least this debt doesn't incur you any fees/interest/charges/etc.