First point about fraud - not true in the U.S. at least If the merchant follows the banks procedures and system and the card is approved, its off the hook. If the merchant commits a fraud or whatever then the bank will deny payment and/or try to recoup payments made.
The fee a merchant pays does not change depending on whether you are using Apple Pay, Android Pay or a physical credit card. So, accepting Apple Pay costs the merchant nothing extra nor does it cost the customer anything extra. The decision by the merchant to accept any credit card payments is the point when the card companies transaction fees come into effect. Apple Pay's fee comes out of the set fee charged by VISA, MasterCard, etc.