Crux of the matter is actual flying time. To KL, it's only 30mins (excluding take off and landing), for distance 300kms. Your kopi might not get a chance to cool off. To Bkk it's 2 hours flying time, for distance approx 1500km. If you include the shebang of tarmac Q for take offs and landing, with ascent and descent -probably 2.5hrs. And if you got tailwind, helps (more so with longer hauls and vice versa if headwind).
Which reminds me of a pilot crony with SQ, who started to fly on Sg/KL route in early years after MSA split. He barely had time to finish his smokes (allowed then) in cockpit. :p