So this take over of the Doklam plateau in tiny Bhutan is part of their strategy to annex an entire Indian state and maybe more.
This small incursion is part of a larger plan for a massive land grab.
I think India will fight this like their entire NE was about to be taken over. It will not be a small and limited war.
If China were to see all of SE Asia countries form a trade association they could challenge China as an exporter and that could scare the crap out of China. China is also looking for a second path to the sea, an easier/shorter route for oil and gas imports from the middle ease.