It's a financial strategy used to free up as much money as possible to enable you to begin to eliminate debt on the lowest amount owed on a credit card. its a strategy when people are in a financial crisis due to over extended debt crisis. Assume you have three credit cards with respective amounts owed of $1,000, $2,000, $3000. You pay the minimum amounts owed on the two larger amounts so you can pay off the entire lowest amount. The snowball goes uphill using the same method . If you have a lot of money you can also use the amount you are not paying to actually buy property and then use that property to secure loans on. Developers use this method often and if the development holds profit it can be used for other secured investments. It's like a reverse pyramid "scheme" except its legal.
Now to the common folk-you and I. Unless your in a serious financial crisis it is always best to pay as much as you can afford over the minimum, if not the total amount, just pay it when its due. Ironically, the snowball effect works for two classes of people. 1) those is a serious financial crisis and 2) those with money that they could pay of the entire debt but want the freedom to buy-mainly land-to be able to secure high loans to keep growing in whatever their investments lead to.
