I just wanted to point this out because I watch a lot of games on Youtube and so far I have never seen anyone use this feature. Once I hit feudal age I build like one stable or one archery range, put the official on it, and it does the work of three. You can mass an army so fast. It also works on the Clocktower which is really useful for massing clocktower springalds.
This has been a public service announcement.