If Tiffany’s performance is good enough, then Tiffany is still best described as optimising for tic tac toe performance, because:
Tic tac toe performance has high predictive power as an hypothesis for Tiffany’s utility function.
Tic tac toe performance has relatively low complexity when compared to other hypotheses with comparable predictive power.
This changes if Tiffany’s performance is not sufficiently high (in which case there may be some other low complexity objective function that Tiffany is best described as optimising).
If Tiffany’s performance is good enough, then Tiffany is still best described as optimising for tic tac toe performance, because:
Tic tac toe performance has high predictive power as an hypothesis for Tiffany’s utility function.
Tic tac toe performance has relatively low complexity when compared to other hypotheses with comparable predictive power.
This changes if Tiffany’s performance is not sufficiently high (in which case there may be some other low complexity objective function that Tiffany is best described as optimising).