Could you tell the difference between a grandmaster and stockfish if playing them online? If not, why would you care which one you are playing against?
Of course you can. Stockfish plays very different compared to a human, and it never ever blunders or makes mistakes.
because we value competence
I think I'd care because the entity on the other side cares about the game in a similar way to me. It's not just the technical details of how the pieces move, it's a human interaction.