The difference is more dramatic as one takes longer to pay off their cards. So your point is well taken, but here’s the rub. If one has the funds and the motivation to wipe out their debt in less than two years, I’d say they are in good shape to begin with. When one has such debt that it will take 4+ years to pay it off, that’s where the $1000 toward your 28% rate compared to the 9% rate has the most impact. That’s $190 difference on just that $1000, by choosing to pay the higher rate.
When I was young and stupid, I found that the high interest cards were happy to give me huge credit lines. It was the 8% cards that gave 1-2K. So my stack of $1K cards had half my balances, but less than 1/4 of the interest cost.
Joe

Why? Because at the starting balances, the cards had the following amounts payable for interest:

$850 card = $6.37 pcm
$2,000 card = $18.34 pcm
£3,500 card = $81.64 pcm (which is more than the minimum payment BTW)
$5,000 card = $41.67 pcm

So the actual balance on the £3,500 card is increasing as the interest is capitalised, or more likely, the minimum payment would be greater.

If you get stuck a year in, the plan wasn’t good. The debt snowball helps breed confidence and change behavior. The system helps you win psychologically, and I want the system to encourage people onto bigger things!