Correct me if I´m wrong, but in SE Asia, it is my understanding that only Indonesia certainly requires the carnet (...about Philippines I´m not sure, though). Thailand, Cambodia and Laos can be done without it. Malaysia´s sort of ´in the middle´ (literally!)..... at least the land border coming from Thailand seemed relaxed about it, in fact they didn´t even bother to have a look at our bike.... but if you were planning to ship your vehicle to Malaysia, then it could be different, as it is officially a carnet-country.
You don´t specify any route, but Australia also requires it, in case you´re planning to continue that way.
In that area, I would not bother to arrange the carnet, unless it is likely, that not having it will become a serious show-stopper.