In the case of China and the yuan I think China had no choice due to market forces.

Simply put: China reacted to market forces and had to devalue the yuan.

Not an exact answer, but something to consider.

China has a slowing economy, I guess they had to do something.

But as I understand China also agreed to allow market forces to play a larger role in setting the value of the yuan.

And yet somehow I doubt it’s all that simple.