Many things in Asia seem strange, inappropriate or even unacceptable. Could be so, but what I also learned is that there is usually a simple and practical explanation behind the action.
A secondary thought while thinking about it was that while relatively less developed, Asia is sometimes much more creative with the tools at hand. In this case - making fire is much easier if the air is blown through a pipe. In that way you won't burn your hair or eyebrows, as we sometimes do, when grilling or sitting near a fireplace during a trek.