It’s about flexibility, being able stay a few days longer, etc. for this short journey AirAsia wants 6,000 THB plus round trip before adding any baggage allowance so it becomes 7,000 to 8,000 Putting it in perspective a trip to Hanoi or KL cost the same or even less. Certainly might consider the flight in and border out for flexibility using website mentioned. Just wanted to make sure they didn’t ask for onward ticket details at the border incase that was decided