is as old as horology itself. We do continue to see today that a significant portion of the R&D of the watch brands go into making the calibre more accurate. Today it is with silicon or graphen or creating new or revided types of escapment. and Breguet patented the tourbillon 200y ago because he wanted to improve the overall accuracy of the watch. The Quartz tidal wave was also to propose more accurate timekeepers.
The competition is within certain rules (the odd one is to keep Japan aside) but the goal is simple: measure precisely which watch is the most accurate after a series of various tests. It does not mean that you would experience the same accuracy when wearing the watch on the wrist for 24h but it is surely somehow related.
What makes this particular edition interesting is the variety of competitors, from independant well known for the quality of their craftmanship to companies that mass-produce calibres and everything in between.
the results I have seen for the gyrotourbillon accuracy is mind blowing (a fraction of second per day in pretty much any position), so I am looking forward to see the results of the others.