Seems like Google is going to open the door for websites to launch a third-party payment app during the checkout process. According to XDA, the new API will be presented on Google I/O this year. New tools are always good news!
The Payment Request API is cross-browser standard that replaces traditional checkout flows. It allows merchants to accept payments in only a single API call, thus reducing the amount of steps to complete the transaction.
Even today, 66% of purchases are made through websites rather than apps. Google's new API for checkout process is an attempt towards better conversion rates on mobile apps by creating a better payment experience for users.