Just so you know, the small print at the bottom of these offers says 5-7 business days. I don't think it takes that long, but it is not instantaneous.
I tested this with the first time gold purchase offer they had earlier this past week. It did take a couple of days to get the reward, but the reward did show up.
I think a number of people are starting to head over here. Not only do they have better rewards for gold purchases, but they are also running forum events and GM events. I am out of town next week, but I look forward to actually having events to participate in when I get back home.