We have a "First Tri" distance at the CapTexTri that is a mini-Sprint. We also have a tri called the Rookie Tri. There are lots of accomplished triathletes that compete in these (including Hawaii Ironman podium girl Desiree Flicker doing the Rookie) for different reasons. Some are training, others excel at the super short distance.
I think of them as marketing to help people who are new to triathlon find easy way to try the sport.