Silica was not just an ordinary Magus. She was one of Lord Izta's trusted generals, her expertise in weapons had earned her the spot of being the one in charge of the Terran army training.
As of now, she carried a hundred years' worth of experience in training thousands of the Terran soldiers. Even before that, she was a renowned combat magus and a fighter that has fought in countless wars.
For her to see Emery and his friends' skills in weaponry, there was no other method that was more effective than battling using combat puppets. Fortunately, as an ex-combat institute instructor, Lord Izta kept several of those puppets within his domain.