I think that the answer depends on what you mean. Would it be rational for China to claim the areas and perhaps become involved in a major regional war? No. Might it happen anyway? I think so.
In the "real world" people and nations do things that are not rational all the time, due to more abstract factors than economic profits. Here we have things like national pride, fear etc. Was the Falkland War rational? In the end Argentina ended up in a worse sitation than it started from. It was a war that came out of national pride and domestic problems.
I am not saying that China will invade and create a major war, but tensions are high in the whole area. Wars may spring out from unathorized provocations also, like the Jameissons raid which caused the Boer War. What if a bunch of fisherman make a landfall on an unihabited island and build themselves a hut were they fly their flag, and then the neghbouring government reacts, thinking it needs to show the surronding world that it has not given up it claims? Things like that have escaletad into wars earlier.