And with Kasikorn you don't need your ATM card to withdraw at an ATM. Just use the card less option on the app. Top up mobile phone, there's lots of advantages of having a Thai account. Sending money from home country and no ATM charges etc.
Some years back I went for an extension at immigration as I needed a few extra days, and they told me no need to extend, just overstay and pay fine at the airport. 🤦