Just a quick one regarding showing the 20,000 Baht proof of funds should an IO ask to see it when arriving and just getting a 30 day stamp. Would they accept it if I showed over 20k in my Thai bank account using the bank's app on my phone or would they insist on seeing cash?
TLDR : Answer Summary
When entering Thailand and needing to provide proof of funds, it is required to show cash rather than a bank balance from an app. Multiple comments confirm that immigration officials only accept cash as proof of funds, specifically citing a minimum requirement of 20,000 Baht.