Tacking downwind is always faster in terms of how fast the boat is going, but it is not always faster in terms of getting to a fixed destination, like the leeward mark.
I thought (and I could be very wrong) that in light air the Hobie 16 actually does better sailing straight downwind, wing-and-wing. But I cannot imagine a whisker pole being necessary for a jib on any small cat -- just a crew with a long, strong arm.
On our Hobie 18 I was the whisker pole, although I really try to be whiskerless. We always tacked downwind, but I had to hold the jib out at the proper position, so I was definitely a whisker pole. It's the same thing on the Hobie 16 downwind.
P.S. It's not like NOBODY sails dead downwind. We do it on our Hobie Waves. It is true of any boat that the slower the boat, and the lighter the wind, the less benefit from tacking downwind and the deeper the angles you have to sail.
And, of course, if you have an assymetrical spinnaker (or Hooter), you have a fixed pole sticking way out in front, so you don't need a whisker pole if your sheet leads are in the right place.