Agree with most answers here.
Snowboard is a lot more difficult than skis with a kite, you'll struggle a lot more to keep up upwind while on skis you can edge to insane angles, easier and faster.
It's also much easier to climb on skis, as you shoot straight up as opposed to sideways.
When you fall on snowboard you struggle to get back up as you fall backwards.
Take off and landings on slopes are much easier on skis.
On skis you can ride at around 300 degress from wind direction, even completely downwind, while you can't on a snowboard.
That said, I ride only snowbaords! Just cause I've always ridden them....