Looks nice! I was curious about the effort needed to replicate this result with the Google Wallet API and it ended up being a nice evening project to pull off. Sadly with a demo account you get an ugly [TEST ONLY] tag in the card title with a non published account, and the customization options of the card itself don't allow much leeway. One thing I miss is being able to change the font color.
If anyone is curious, I followed this guide: https://codelabs.developers.google.com/add-to-wallet-web#0