I recently purchased a CycleOps indoor trainer and saw two different chocks for the front wheel of the bike I'll be using. One just elevates the wheel enough to level the bike, the other has multiple positions to raise the front of the bike by several degrees. Being there is no actual climbing taking place, the amount of force to spin the rear wheel will not change. The only change I can see is the rider's orientation on the bike and then only by a few degrees. The salesperson was adamant that the significantly more expensive riser was a training advantage and you could even stack them.

Am I missing something? Is there an actual and significant advantage to elevating the front wheel a couple of inches on a stationary bike?