Here is what I understand.
1. They told me you had to book while at WDW. Not sure about first time buyers or adding points.
2. Its for purchases at BCV, since they aren't making it available until later this year. Basically you are buying your points at $70 per point instead of the current $75.
3. You also have an option to select from a free vacation week, depending on the number of points you are purchasing. There are a few restrictions and the stay has to be consecutive nights.
All in all, I prefer the $5 rebate option, since we are locals and I don't do full one week stays, I am a weekender or long weekend Disney person.
Anyone else, please feel free to add.