Even if the so called 'trap' doesn't make any sense, this is still pretty enjoyable for a battle manga. The twists and turns at least have setup and execution, rather than feeling like they're pulled out of thin air every chapter.
(Seriously though, if that's the nature of magic circles, why not just make a bunch of magic circles in your own territory and break them yourselves? Spending the effort to trick the enemy into doing it for you doesn't really improve the strategy.)