Today was the first arrival with TDAC. I'm a NonB Visa holder and filled the TDAC 2 days ago. The App worked fluently, within 10min. I had the download with QR code. The immigration watched my Passport and Visa but surprisingly did not ask for TDAC. When I was asking why, she answered that all data are already in her computer. Fingerprint, picture, stamp in passport and within 30sec. I was through. In my opinion the TDAC is one of the best ideas Thailand ever had, as the immigration awaits you and your data are already approved. They don't ask any question, just say hello, stamp the passport and you are good to go.