Think he means because "Deploy" and "Fight" both allow you to keep invisible but "Assault" wipes it. Not sure the reason, probably the fact of avatars are so easily replaced maybe?

BST pets are on a 5 minute timer + jugs, and automaton are 5~20 minute timer. And while PUP and BST can hold more of their own without a pet, they don't want to keep us without one at our side?