It explains why the demon would be different than human. Demon can learn if the demon has interest. Yet human can be stubborn to not learn even when the human has interestI think Gluck is weirder and more incomprehensible. He's just as emotionally detached as Macht and he doesn't even fake it. He accepts Macht/demons as they are. He basically scoffs at the idea of Macht understanding "malice" and the bracelet being able to do anything. And yet there's this weird friendship/understanding happening.
Macht in a way feels more human with his "I told you so" when Gluck's daughter married Denken. I feel like I can comprehend Macht way better than Gluck.