First - a lot of grade school is just babysitting. It's definitely not a cramped situation of required learning. Point being, there's little lost opportunity cost here. Assuming kids are getting the fundamentals ... there's lots of time for more, decent learning.

Second - any second language skill is going to be immensely useful as a learning tool. It really helps one understand language and communication.

Third - Chinese, it would seem, is likely going to be a useful language in a country receiving considerably Chinese investment.