why are banks aggressively pushing these credit cards?

Are credit cards a bane or boon? It depends on which side you are. If you're one who is a delinquent user of these cards, then it could be your daily nightmare.

Are credit card companies making good in this business when there seems to be a lot of disgruntled customers and bad debts? Must be, if not, then why are banks freely giving away credit cards to its clients who are in good standing?

My sister received not just one but a multiple of credit cards from various banks. She was surprised because she did not apply for them. Another friend also was handed a pre-approved credit card which she did not ask for. Does this mean that business is doing well with these credit card companies? Hmmm.....makes me not wanna think about it.