I don't think you're correct about the cash advance - as I recall the merchant only gets paid when the coupon is redeemed. Groupon keeps the float and the breakage.
Another thing to realize is that they get the money REGARDLESS OF WHETHER YOU REDEEM IT. EVER. Depending on the type of Groupon, upwards to 20% of them are never redeemed (this is a dirty secret of gift cards, too).
http://venturebeat.com/2012/05/07/groupon-tightens-its-payme...
Another thing to realize is that they get the money REGARDLESS OF WHETHER YOU REDEEM IT. EVER. Depending on the type of Groupon, upwards to 20% of them are never redeemed (this is a dirty secret of gift cards, too).