To me, cashback is CASH BACK. When I bought a camera last fall from Adorama, I did get a AMEX card back which I could use almost anywhere.
However, the fine print reveals otherwise.
Purchase any eligible product and receive the specified percentage back in Rewards points (Currently not available with Google Wallet). The percentage is calculated based on the price you pay for the eligible merchandise; tax, shipping & handling and any other fees are not eligible for Rewards points. Your order must be placed while you are logged in to your B&H online account. If you fail to do so, Rewards points cannot be applied retroactively.
Approximately 40 - 60 days after shipment, your Rewards points will automatically convert to a promotional code that can be used on any item we sell. You must use the promotional code within six (6) months of the date it is issued.
Your billing and shipping addresses must both be within the United States. If you return an item for any reason the Rewards points will be voided. We reserve the right to modify or cancel this program at any time without prior notice.
6% back is 6% back. They all know we buy from them all the time. The kicker is the part you can't use it with any other promotions which any sale off their regular price is. If you buy this camera at this price they will refuse the 6%. Whether it cash back, or off your next purchase it doesn't matter, you will not get it.