What the other guy said is sorta right, the bank DOES want the person who is going to be unreliable, but being unreliable is what leads to a bad credit score.

Having a good credit score is what allows you to get more credit and better offerings which you can use to get free money or travel miles

Think of credit score as the ranking creditors give you, the higher the number, the more they trust that you will be able to pay that back.

A few categories make up how it is calculated such as your payment history (are you making payments on time), utilization (say you have a credit card with $1k limit, using 95% of that is bad), overall lines of credit.