There were numerous issues. First one (somewhat mitigated lately) was extremely large number of actions per minute and (most importantly) extremely fast reaction speed.
Another big issue is that the bot communicated with the game via a custom API, not a via images and clicks. Details of this API are unknown - like how invisible units were handled, but it was much higher level than a human would have (pixels).
If you look at the games, the bot wasn't clever (which was a hope), just fast and precise. And some people far from the top were able to beat it convincingly.
And now the project is gone, even before people had a chance to really play against the bot and find more weaknesses.
Another big issue is that the bot communicated with the game via a custom API, not a via images and clicks. Details of this API are unknown - like how invisible units were handled, but it was much higher level than a human would have (pixels).
If you look at the games, the bot wasn't clever (which was a hope), just fast and precise. And some people far from the top were able to beat it convincingly.
And now the project is gone, even before people had a chance to really play against the bot and find more weaknesses.