I called to find out about this deal too. I was told the following:

3 points per dollar spent at Marriott
2 additional points -awarded from Marriott because you become a silver elite member
1 point for all other purchases on the card

So, depending on how you look at it you are getting 5 points for each dollar IF you were a basic member like me. If you are platinum you get a bigger bonus from Marriott so I guess you get more points.