Not sure where you're getting those numbers from. The article talks about paying 90% for a Best Buy card and selling it for 95%, while 1800 Flowers sell for about 70% (no CardPool purchase noted).
Ah, I guess I skimmed over the middle of the paragraph, and just saw the 1-800 Flowers at 30% off. So, I guess they're hoping to sell a whole lot more cards at 1-9% off than 10-30% off. I knew I was missing something obvious.