[IanCal]

This is overly reductive. Understanding what they're doing at a higher level is useful. If you knew enough about neuron activations and how they change with stimulus that wouldn't be enough for a human to develop a syllabus for teaching maths even if they "understand how people learn".

What you describe also doesn't answer the question of how to structure and train a model, which surely is quite important. How do the choices impact real world problems?