Well, I did a little math and here is what I found. It takes me 3.5 minutes to print 7 coupons at 10 cents each. I'll round that up to 4 min. since you may not be as quick 
So if you essentially earn 70 cents every 4 min. then that translates to 10.50 per hour. So when you look at it from that perspective, it doesn't seem all that bad. Yes I know your not actually printing for 1 hour in a row, but like I said, when you break it down it's not too bad. If I remember right, I think some people were saying that they were averaging less that 1 buck per hour swiping with CellNuvo. Maybe it's "apples to oranges" but interesting none the less......
4 minutes a day x 30 days a month=120 minutes a month=2 hours a month to make $21which divided by 2=$10.50 per hour x 2 accounts x 8 minutes a day=$42dollars a month. As you rightfully say, not bad at all, save for having to show up for work 7 days a week for robotic printing duty. Of course, the time spent checking for math errors in the rewards app has not been factored in yet.