Or...just use the Starbucks app for Samsung watches (https://galaxy.store/sbcoffee) It's called "SB Coffee Card". It does other nice things like keep the display max brightness for 20 seconds while you scan your watch at the cash.
Why not just use the Starbucks app for Samsung watches? (https://galaxy.store/sbcoffee , the app is called "SB Coffee Card". Way simpler than trying to integrate with phone wallet, etc.