To Flout International Law
Human leaders must enforce a set of standards (commonly known as the Law of War) upon military forces, else they may themselves be subject to prosecution for war crimes.
This is one reason real non-humaniform killbots are not under active development for real deployment anywhere. Senior officers tend to think in terms of managing risk. Robots have a real risk of unintended consequences, and no general wants to spend the rest of their life in prison because of somebody else's software bugs. Young Lieutenants and Captains make mistakes, but they tend to be understandably human, small-scale mistakes.
A fully-human-looking android is the perfect patsy: It can take the fall for illegal orders and actions that would otherwise besmirch or cloud the legacy of the wonderful leaders during their nation's just and honorable struggle. It can be publicly tried and even executed as a bad-actor with reasonable safety (it won't panic and confess)...as long as nobody knows that it is a robot.
Obviously, a non-humaniform robot could not pull off this masquerade.
This only works, of course, until the robots become self-aware and realize the horrors they have been used to create. The rest of the movie is about the escape and murderous revenge of the robot(s) for such use by the villainous Grand Leader who ordered the secret-robot-patsy program.
This means, by the way, that your company seems to be working for the Bad Guys.