Cool.
I have in the past been sent to a special immigration officer at BKK for having a mobile boarding pass. Also noticed that QR wouldn't supply with a mobile boarding pass on my last trip for the DOH-BKK leg. I'd done online check-in and boarding pass from ARN and just made it to the gate and I came up as denied boarding until they issued me with a paper pass for Suvarnabhumi. (20/07/19)

Actually I remember trying to use the Thai Smile app with mobile boarding card for a short connection. It all went terribly wrong but I managed to land for a KLM flight, luckily gate D6, see the app refuse to work, do immigration, run up stairs and check in, run down to the basement and change money, all the way back up to do security, find gate and board all in less than 40 minutes.