Puppetmasters are an Aht Urhgan specialization. Story-wise, it would make no sense for you to command or configure a Cardian in the same way as you would an automaton, especially where Ghatsad is involved (as the person above me stated.)

And besides, (more spoilers, highlight message to read.)
Mnejing and Ovjang weren't exactly optimized for combat purposes. To pit one of them up against the King of Hearts? On the other hand, I'm sure a standard automaton from a fairly devoted puppetmaster could outperform the Windurstian Cardians.