For Platinum (and Centurion too I'd imagine) this is 4x points (another one of those small benefits that really does add up to make my annual fee worth it I think).
However, BonusPointsMall stipulates an additional restriction that most sites do not have: You may not use any other coupon, special offer or promotion code when shopping on a Retailer's or Travel Provider's website and Company cannot award bonus points for any purchase made through a third party retailer or other Retailer or Travel Provider that may be linked to a participating Retailer's or Travel Provider's website.
The one site I use BonusPointsMall for on a regular basis is Staples, I always use a coupon with my Staples purchases, and I've always gotten my bonus miles. I think that language covers them just in case ... can't really complain if they give you the points even though you used a coupon, but if you didn't get the points because you used a coupon ...