No, it's not a model of a human brain, like bicycle is not a model of human legs. It's artificial intelligence. There are similarities, but we cannot use current AI models to study human brain: it's useless for that job.
We can create a model of human brain (Artificial Brain) using a bunch of AI models, of course, but it's not done yet.
A model doesn’t have to be useful to study the thing you’re modeling, you can also just be interested in the output because it’s simpler than using the original thing. Modeling a human brain with a neural net and using it is simpler than directly simulating a human brain, so that’s what we do. Not being useful to study humans brain on doesn’t mean it’s not a model.
A model of a model of X is also a model of X. It absolutely is a very simple model of human walking. You’re just using „model“ in a very narrow sense that excludes many things that are commonly called models.
Models are used as orders of magnitude cheaper substitutes of real thing in learning, predicting, and so on, known as «modelling».
AI, in it current state, is not good enough to serve as substitute for human, or human brain, but good enough to serve as substitute of human level intelligence. At this point, we are able to model brain of a fly.
It looks like you are confused by similarity of scheme, model, and similarity.
A model needs a map to transfer knowledge in both directions: from a real thing to a model, and from the model to the real thing, while in scheme, knowledge is transferred in one direction: from a real thing to a scheme. They toy humanoid robot is just a schematic representation of a real human.
Moreover, similar things are not models of each other. Apes are not models of humans and vice versa.
It just depends on your definition of a model, but to me, a neural network is modeled after how a human brain works.
If Apes were man-made, I would also count them as a model of a human.
We can create a model of human brain (Artificial Brain) using a bunch of AI models, of course, but it's not done yet.