Is there a Starbucks app or widget for Galaxy Watch 3?
I can use my watch to pay for almost everything - Grocery, Dining, Department stores that is very convenient as I do not have to get my phone out.
Except for Starbucks. Does the app exist for US?
Korea has debuted in 11/2017.
The app is not supported by Samsung but there's a third party app that's called "SB Coffee Card", just look it up on the Galaxy Store under the "Watch" section. You have to pay for this app but I think it's totally worth it for contact-less payments. I have personally been using it for a while and it works great!
Hope this helps.