They can already take a photo of your credit card and use it online. The whole point of Apple Pay is that you don't give out your credit card, so it's more secure.
Don't be too sure about that. In 2012 I went through 6 Mastercards. My bank narrowed to down to 3 possibilities. One was Apple who has my credit card on file. During that conversation they stated Apple had had unauthorized access to people's records. Because this stuff does not need to be reported, and most merchants do not report it, does not mean it doesn't happen or its safe.
----------
The banks and credit card companies are now pushing for it because lets face it, the current system is a joke security wise with near constant fraud and hacks (like the target hack).
The current system has been a joke for decades. As long as the banks can pass their losses back to their customers, they have no incentive to battle the merchants.