Checkout is offering free processing for all its merchants during the holiday season. This is just another incentive to offer its merchants to encourage them to use the Checkout platform. Paypal, 2Checkout, and Authorize.net still have a huge share of the market compared to Checkout.
With every bit of encouragement, Google wants to bring more clients and merchants to the platform to start giving it more of a brand image that is recognized and accepted across the world. Google entered into a market that was new to them and they need time to become a player in the industry.