If you have € 1000 on a credit card at 18% interest, the interest cost you 180 €. If you save € 1000 in a savings account with a 4% interest after taxes, you earn € 40 in interest. If you pay 1000 € to you with your savings you save 140 € per year.

It’s that simple, debts usually cost more than you earn on savings, so it is best to cancel debts to save.

When you save, you do really is to pay your money to the bank for use and lend it to other people. The difference between the fare you paid to you by letting the money to the bank (savings rate) and the rate it charges other people by loaning them money (the loan rate) is your profit. Therefore always costs more to borrow money to be earned saving.
Exceptions

This is based on the fact that the cost of debt is generally much higher than what you earn from savings, so that your finances get much better is you get rid of your debt if you start saving.

The exceptions are the few occasions when the debts are cheaper than the savings, or cost of pay is very high:

The exception to the penalty: If paying your debts is a penalty, as can happen with some mortgages or loans, then you better save and put your money in a savings account until the penalty is small enough not to import .

The plea of no interest or very low interest rates: This concept is entirely based on the fact that debts cost more than they earn on savings, but if you do not have interest in your debt, you must follow the opposite logic. If the interest rate on your debt is less than you make with your savings after tax, provided you’re disciplined, you better save and not paying your bills with that money.
Is it worth it to have money saved for emergencies?

For a person who has no debts or to pay for penalties, the most advisable would be to have money saved for emergencies, but for anyone with large debts, particularly credit cards, not worth it.

Example: If Laura has 5000 € saved, earning a 4% interest after taxes, for emergencies, and should also € 5,000 on credit cards. While your savings will rent 200 € per year, your debts will cost 900 €, so it actually pays € 700 per year. If you pay your debts with the money saved, or earn money from savings or pay interest, which would save € 700 per year.

This is advisable if you can get money in an emergency. Generally if you have credit cards you can get the money, but if you’re going to pay a personal loan and have no other means of raising money in an emergency, you have to consider.