My bad. I was looking at portal rewards for gift card mall and not staples. Whoops!
So online they are 7% fee ($7 charge per $100 card) at staples.
For absolute cash value (not UR equivalent value), that is 7% in fees against (5% UR + 1% visa savings edge + 3% TCB). Looking at 2% margin, or $20 vs the $25 (2.5%) by going in store.
Pro
free shopping and don't have to drive to staples
Con
Twice as many cards to unload ($100 vs $200) at a Walmart money center machine for BB.