You don't move any faster, it only looks that way because, graphically, the square is widest at the diagonals. I would've thought that this was obvious.
I am stunned by the authority with which you made this false claim.
How many moves does it take to move a king* from one corner to another on a chessboard? Did you notice the answer is the same for opposite and adjacent corners? (You do understand that opposite and adjacent corners are different distances away?)
Chess players have known the OPPOSITE to your claim for hundreds of years when studying king moves in the endgame. It is an established fact diagonal paths fail to preserve distance on square grid gameboards.
- O
* or a civ unit