The “safest” for the bank IS the person who is unreliable. The fees for no-, late-, or under-payments (and interest) all go to the bank. So really the ideal customer is someone who uses a lot of their credit, and isn’t the best at repaying under the agreed terms. What they really want is someone who makes occasional or frequent mistakes, but at least tries to keep up.

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

Credit cards just seem to be used fundamentally different in your country.

In Western countries it's expected that adults will have at least one credit card. So many things can be tied to that card. A big one is automatic bill payments. Not all can be tied to your bank account. So when you go to apply for a mortgage the bank is expecting you to already have a credit history. If you use your credit cards right it means you never miss a payment. Even better if you don't carry a large balance on them. The bank will see your payment history and can see how much of the credit card you are using. It then uses this info as part of its calculation on what kind of mortgage it's willing to offer you.

If you don't have a credit card the bank has no history to use in it's calculation. It has no idea how good or bad you are with other people's money. It's still possible to get a loan or mortgage without a credit history but it's harder. The bank will relay way more on the other information you give so often you will need a much better job or more assets for them to be confident that you will pay them back.

Having a credit card doesn't mean you are bad with money on its own. It's entirely based on how you use it. Normally when you first get a credit card it might be a secured one. These have very low limits and you need to pay into them before spending money. These are designed for people with no or poor credit to build up a good history. Once you have a history or a better one you should move to an unsecured card. This is what people think of when talking about credit cards. These have larger limits and you get a bill every month showing what you owe, your minimum payment, etc. To maintain a good score you don't need to fully pay off the balance. You need to make at least your minimum payment and it's good to maintain a low level of utilization. This means that if your limit is 10k, your balance is say 3.5k or maybe up to 5k. If you maintain a balance near 10k this is noted in your history. Some people really overreact to high utilization. It will make it harder to get more loans but it doesn't really lower your score. It more pauses it while you pay down the balance. However regardless of whether or not it's affecting your score is the fact that that balance is costing you a ton in interest. Bank loans usually have pretty low interest while credit cards are often 3-5 times higher.