The reef points were taken out of the Hobie USA sails in 1985 when the CompTip was introduced. Since most of the rest of the world still has solid aluminum masts, they still have the reef points.
However, in 31 years of racing 16's, I can't remember ever racing with the main reefed. Usually if it's so windy that you'd want to reef, the race committee bails out.
As I recall, upwind performance suffers significantly when reefed; downwind is where you really want to reduce sail area to avoid the pitchpole. There are other ways to reduce projected sail area downwind (like traveller/sheeting in) that work just as well.
Might be handy in a distance race, though.