Less weakspots in the wheel that can deform the hub rather then if it were 6. In between spokes there is an even gap when the wheel rotates and the gap between spokes is sort of a weakspot. You have to understand that the force applied works in 2 ways, the bottom of the wheel and the top. (bottom spoke pushed down on, top spoke pulled down) What an odd number does as you can figure is minimises this gap in top/bottom between spokes thus allowing the flex that the wheel needs with out being too solid(slows wheel down, no flex/rebound) thus aiding the rebound of the pu which that inturn can affect every aspect of the wheel even the grip you have. Pretty much the reason spoked eagles are one of the fastest wheels as this effect is more effective in a light wheel