One is that he remains true to redesigning his astronomic watch from 1987. The other reason could be that a regulator time display comes from the scientific side of horology, where you can get a very accurate reading of your Chronometer. So I think he wants to display that the watch as a chronometer watch or “scientific instrument”, that still takes accurate timekeeping very seriously. His criticism of these multiple complication has always been that the isochronism is comprised because the power needs to drive so many complications.