As bookkeeper says, most people get the idea of “credit” being a good thing because that’s what their bank statement or credit card statement says.
You go into the bank (in the old days ), you say “I’d like to put $100.00 on my Visa bill,” and the teller says “We’ll crédit your account.” So you think, “a credit is a good thing”.
But the reason they say “credit” is because that means by paying off the bill, you have decreased the asset value of your credit card account, from the bank’s perspective, so it’s a credit entry.
(The payment has simultaneously increased the bank’s cash on hand, an increase in that asset, so it will be a debit to that account in the bank’s books.)
If you were keeping double-entry books for your own budget, you would enter the payment to your Visa account as a debit, because by paying the amount owing, you have decreased your liability. On your books, it’s a debit, on the bank’s books, it’s a credit, from your respective perpectives.
Again, go back to the definitions of debit and credit I gave earlier.
A transaction goes on the debit side of an account if it increases the assets in that account, or decreases the liability.
A transaction goes on the credit side of the account if it decreases the assets in that account, or increases the liability.
From your perspective, making a payment on your credit card reduces your liability on the credit card account, so on your books, it’s a debit.
But from the bank’s perspective, that payment has decreased the asset value of your credit card account, by reducing the amount owing to the bank. So the bank records it as a credit.
The same transaction is thus a debit from your perspective, and a credit from the bank’s perspective.
But because the average consumer doesn’t keep double-entry books, they only get a credit card from the bank’s perspective, which shows the payment as a credit.
One final point: if you have a line of credit with the bank, and it’s maxed out, do you see that as a good thing?