Here's a better example: If you have a computer with a world champion opening book that looks 3 moves ahead, and have it play against a computer with no opening book that looks 4 moves ahead, the computer that looks 4 moves ahead will win almost every game. Actually, it'll probably win every game. This 'more tactical' personality will win because you can't win the game without tactics.
Interesting point!
Why not play the Spanish four knights game?
Because it is much easier for Black to equalize against the Spanish four knights and it doesn't have the lasting pressure that the Ruy Lopez has.