I've lived in Malaysia and Singapore. We don't use disposable chopsticks that often. We usually do when we take away our meals. I travel to Taiwan quite frequently. Surprisingly, they use disposable chopsticks and utensils very often. Restaurants use plastic and paper plates to serve as well. I remembered asking one of the locals there why this was the case. And they said it was to save water.

The issue isn't about chopsticks. It's about disposables. Chopsticks is a mere subset of them.