well I can understand why it wouldn't mind having human puppets going around killing the Totomos it can just get mass produce more and it allows it to test the effectiveness of different designs and get rid of defective models while keeping potentially dangerous humans away from its core.... Although at this point I wouldn't be surprised if Noah hasn't already designed itself a more mobile and perhaps even humanoid form. Depending what's available in this setting it could even have a chance for passing itself off as human for perhaps short periods of time.