Constant taxation at 200, even if you're patrolling, is petty bad for your economy in the long term. Your capital's population will be dropping at an unpleasant rate.
I figured if it allows you to build a massive army you can do alot of damage to the enemy, which could make it worth it. In small 1v1's it seems to be effective for killing quick, but if it is doing alot of damage to my economy i'll stop doing it in big games.