That was likely me. Kinmen is essentially a free pass for China to take to test American resolve. Don't get me wrong, we aren't going to cruise missile Xi Jinping over it, and the Chinese don't think that either, but Kinmen is a good exercise to see if the US is willing to permanently house troops on Taiwan or bolster their defense budget more than we already do.
It helps China's cause that the island is within sight of the Chinese mainland and would likely face no resistance in it's capture - I doubt the Taiwanese troops on the island will be ordered to sacrifice themselves in a pointless defense over it. If there's a part of Taiwan that China has an honest claim on, it's probably Kinmen Island, to be fair.
I put an assault on Kinmen (or possibly another island in the strait) in the next couple of years and an actual invasion of Taiwan in five. China wants to be "whole" by 2047. That includes the South China Sea, land claims in the Himalayas, and most importantly claims on the Russian city of Vladivostok. They've got to start moving if they're as serious as they say they are.
Edit: Someone prior had mentioned "regional powers" of the next century. France was listed, which I agree with. France and Poland are both set to become the military pillars of Europe as Britain and Germany wane. Poland appears to have taken the adage of "never again" quite seriously.