I have, use and like the ski key.
The disadvantage is that your resort has to have the appropriate racks. They're common enough in the East, but I'm led to believe they're less so in the West.
The other downside is that there are less board slots per rack than ski slots so you might have to hunt around for a free slot to use.
You can fit 2 boards base to base in a slot and just use one key.