Yes. TG/PG or even WE (to an extent) use a lot of bus gates because BKK is their hub airport. It is not about saving cost but it is more about not having to move empty aircraft from one place to the other with a push back truck.

When you get a bus gate, it’s one of the following:

- You’re on an international flight but plane parked on domestic gate.
- You’re on a domestic flight but plane parked at an international gate.
- You’re about to board a flight where the plane was idle for more than 3 hours (so it did not park at a gate because they did not want to pay the airport the opportunity cost).
- You’re just disembarking from a plane that has no scheduled flight after your flight for more than 3 hours.