Fingerprint authentication adds secondary authentication before a transaction can be initiated. Additionally, it makes sure that nothing get's bought by accident and doesn't require remembering anything such as a password or a pin to use.
Google has a partnership with Bancorp Bank that issues a Virtual Card to Google Wallet users that works as an intermediary between customer's card and merchant. It gives more choice in terms of compatible cards and works as a card fraud mitigation technique.
Samsung Pay supports Magnetic Secure Transmission technology that allows using the phone to swipe near a credit card swipe reader to pay. The technology currently is only supported in Galaxy S6 and Galaxy S6 Edge phones.
Android Pay functions as a platform that allows third-party developers to create payment apps on top of it not as a standalone app itself. This potentially will enable higher competition between available frontends and as a result better solutions without having the payment information tied to one...