Because banks have done KYC of the customers before issuing and credit card to the person. If you can do the KYC yourself and establish the identity then you do

Because banks have done KYC of the customers before issuing and credit card to the person. If you can do the KYC yourself and establish the identity then you don't need to use credit card as anti-fraud mechanism. SaaS companies already ask credit card for billing so it in a way also became a way for anti-fraud detection.