You're dancing around, and haven't really defined, what it means to "learn Go." Sure, humans wouldn't become better at Go. But that's a limitation of the human

You're dancing around, and haven't really defined, what it means to "learn Go." Sure, humans wouldn't become better at Go. But that's a limitation of the human brain (we're not good at mathematical memorization and computation). For all we know, what the network has learned about Go (a highly complex and interconnected set of statistical dependencies) is what there is to learn about Go. You're implicitly making the assumption that what the network learns about Go is guaranteed to be translatable to something humans can learn. On the contrary, what the network learns is merely reducible, with loss of accuracy to what humans can understand. And that is an active area of research (feature visualizations and explanations), but that is tangential to your point.