Because while you could get something that drives a dumb interface, by moving the work and data to the server it's not available for the emulation software to use.

If the contract is well defined, the LLM can infer what it's purpose is, implementation, possibly even your secret sauce. There is no software moat anymore.

yes this is what i was trying to say. its quite common on older client-server games to do this sort of thing. powerful ai models will just make the work to recreate/emulate servers faster.

Except that emulating what is seen is surprisingly useful to find attack vectors. As a single deeper datapoint, one can look at more than just baseline behavior and delve into timing details to further refine implementation guesses.