The reason your credit card company cares more than eBay or PayPal or any of these other non-credit services care about it's twofold. First I do believe it's because you're their customer and there is a lot of competition in the credit and banking industries. eBay doesn't have a lot of effective competition in its area. There are other auction sites and other places to purchase things but not all things are listed everywhere and so you don't have the ability to just pick and choose where you purchase from specially for odd items. For choosing which bank is going to issue your credit card you have many many many choices and they all work about the same and differentiate themselves based upon their extra amenities and services.
The second reason your credit card company cares is because of the Fair credit billing act. It is written into law that they must have this chargeback policies and so forth and these other consumer protections. If it wasn't law would they have them probably not but because it is law they stand behind it and it becomes a feature that they were forced to issue that is a good selling point. Because unlike dispute policies written and enforced by a company all by itself with no law behind it if you disagree with how the dispute is handled by your credit card company you actually have legal protections and legal recourses behind it.
The second reason your credit card company cares is because of the Fair credit billing act. It is written into law that they must have this chargeback policies and so forth and these other consumer protections. If it wasn't law would they have them probably not but because it is law they stand behind it and it becomes a feature that they were forced to issue that is a good selling point. Because unlike dispute policies written and enforced by a company all by itself with no law behind it if you disagree with how the dispute is handled by your credit card company you actually have legal protections and legal recourses behind it.