Originally Posted by goodeats21

Are you maybe thinking of the M+ app thing? I have never received a gift card "on the spot" from using the shopping portal.
The OP was asking about buying a physical gift card at the BB store, then using it on the M+ shopping portal to pay for a new purchase, rather then using a generic Visa / MC etc.

I would give it a shot, and would say it is 50/50 on if it works. IIRC, some websites indicate that GC will not count toward mileage, along with shipping charges, and promo codes not available on M+. But the logic behind it is not always 100% accurate.