Yes...
> That is, it figured out that it needed to allocate 64 binary values and swap some of them after each move.
Yes, but "figured out" is misleading.
It didn't invent or "figure out" the model. It discovered it, just like any other pattern it discovers.
The pattern was already present in the example game. It was the "negative space" that the moves existed in.
> "Strategy", meanwhile, has nothing to do with anything. The AI wasn't trained on competitive matches - it had no way of knowing that Othello has scoring, or even a win condition. It was simply trained to predict which moves are legal, not to strategize about anything.
Yes, and that is critically important knowledge; yet dozens, if not hundreds, of comments here are missing that point.
It found a model. That doesn't mean it can use the model. It can only repeat examples the of "uses" it has already seen. This is also the nature of the model itself: it was found by looking at the structural patterns of the example game. It was not magically constructed.
> predict what moves are legal
That looks like strategy, but it's still missing the point. We are the ones categorizing GPT's results as "legal". GPT never uses the word. It doesn't make that judgement anywhere. It just generates the continuation we told it to.
What GPT was trained to do is emulate strategy. It modeled the example set of valid chronological game states. It can use that model to extrapolate any arbitrary valid game state into a hallucinated set of chronological game states. The model is so accurate that the hallucinated games usually follow the rules. Provided enough examples of edge cases, it could likely hallucinate a correct game every time; but that would still not be anything like a person playing the game intentionally.
The more complete and exhaustive the example games are, the more "correctly" GPT's model will match the game rules. But even having a good model is not enough to generate novel strategy: GPT will repeat the moves it feels to be most familiar to a given game state.
GPT does not play games, it plays plays.