Manders is spot on. Baller99, it's not the best coaches available. It's whatever (usually young) coach is prepared to turn up at 6am for free and run some shooting drills.
In the past 15 years, I cannot think of a single player who has improved from SDP. The majority of kids do it because if you don't you can't make a state team. In reality, the majority of those players were never a serious chance of making a state team in the first place.
Money grab and creating the illusion that they are developing players.