[freeflight]

If you learn, why not learn from the best, the pros? These people already have spent years figuring out what works and what doesn't. Why not draw from that pool of knowledge and instead spend extra time going through the same motions?

[MereInterest]

Because then you don't know whether the AI learned by experimentation or by mimicking. To draw an analogy, imagine the difference between somebody reading and following an algorithm to solve a Rubik's cube, as opposed to somebody being handed a Rubik's cube and experimenting. If expert-level strategies can be reproduced without being explicitly shown to the person/AI, then it means something is going right in your methodology.

[kadoban]

Two reasons I can think of:

An AI trained from human strategy might end up more limited than one that could learn from scratch. It could be stuck in a local maximum of play and be unable to escape.

An AI technique that requires a large dataset of pro play to learn will be much more limited in terms of applying it to other games.