No I’ve not missunderstood the task at all. For the task to work and not fail you very much have to be able to service the debt. If you don’t have sight of that then you are much more likely to fail.
If you can’t afford £250/£500/£1000 per month then you can’t afford it, regardless of if that is to put in savings of spend on mmp’s, so if you can’t afford that then you can’t service the debt.
I wouldn’t call £900 a month a minor flaw to over look when the impact of screwing that up just once can remove the entire benefit of stoozing.
Your missing it. Say you get a 3 month card (silly short term to just talk through a simple example).
Month 1, you spend £1000, you save £1000. You would have had to pay the £1000 off via debit/normal credit card so you have £1000 more free cashflow than not using the 0% card.
Mnoth 2, you spend £1000, pay £50 in minimum payment. Save £950. Net debt £1950, net savings £1950
Month 3, you spend £1000, pay £100 minimum, save £900. Net debt £2850, net savings £2850.
Month 4, you close the savings and pay the debt.
At some point you will gain interest on the amount that sat in savings.
An extreme example would be where your minimum payments were matching your spending. At that point your net savings is unchanged, your net debt is unchanged.
But, you would have a large amount in savings matching your net debt. (Plus of course at some point interest getting added).
If above £1000 was monthly spend and minimum was 5% then you could have 1000/5% = £20k of debt interest free whilst the same £20k was earning interest in savings.
Unless you had strange spending habits its basically impossible for your outstanding debt to require minimum payments above the amount you would have had to pay if you were not using the 0% card.