This article just answered my question about the Microsoft band:
Third-party Starbucks app Buckstar drops reward card support amid security changes | Windows Central
"Starbucks is evidently very protective of their user data ? as they should ? and previously have had apps pulled that authenticate against their API without their consent"
So why can they not allow at least a trusted company like Microsoft to connect to the API with their own app? Or is it that Microsoft is not interested in doing that either, since it seems the Band is merely a bar code image with no actual connectivity to Starbucks. I guess if you already wear the Band, it would be slightly better than also having to carry the card, but that's the only advantage..
"Like any other rewards card, users can still generate a barcode to be scanned at Starbucks to redeem points or their balance. Even the Microsoft Band does this by generating a simple code through the Microsoft Health companion app. However, to our knowledge, what is on the Band is all Microsoft's initiative, and it has nothing to do with Starbucks giving consent or cooperating."
I guess I could just generate the barcode and store it as an image on the phone lol