Update: Now it's not a question of whether it hurts, but how much... Thanks BenH for his report at post #23: http://www.flyertalk.com/forum/20872978-post23.html

Short summary is that at least 2 types of reloads (VR, MP) are not receiving cash rewards. Gift cards are still OK for now.

End of Update.

Just read from another thread that Amex is not giving cash rebate to "reload" cards. It's quite surprising that no discussion here. I checked the T&C in Amex site and indeed it is buried under "Terms and limitations apply" -- you have to click the tiny sign (†) to see it. (https://www.americanexpress.com/us/c...sh-back-cards/)

Now the question becomes whether gift cards are considered "cash equivalents"? It's quite chilling because in that same thread someone reported claw back of reward dollars by Amex (though for a different reason). What if one year later Amex wants you to return all the cash back because it's earns on "cash equivalents"?

Amex T&C (bold is mine):

Cash back is earned only on eligible purchases and is earned in the form of Blue Cash Reward DollarsSM (reward dollars). You can redeem reward dollars for statement credit, merchandise and gift cards, whenever your available reward dollars balance is 25 or more. The number of reward dollars you earn is based on a percentage of the dollar amount of your eligible purchases during each billing period.

Eligible Purchases means purchases for goods and services minus returns and other credits. Eligible purchases do NOT include fees or interest charges, balance transfers, cash advances, purchases of travelers checks, purchases or reloading of prepaid cards, or purchases of other cash equivalents. Additional terms and restrictions apply.

You will earn a reward of 3% on the first $6,000 of eligible purchases in an annual reward year at supermarkets located in the U.S. (superstores and warehouse clubs are not considered supermarkets). An annual reward year is 12 billing periods in a row starting with the one that begins in January; 2% on eligible purchases of gasoline at gas stations located in the U.S. (superstores, supermarkets and warehouse clubs that sell gasoline are not considered gas stations); 2% on eligible purchases at select department stores located in the U.S. (The current list of select major department stores at which you can earn a 2% reward is available at americanexpress.com/rewards-info); and 1% on all other eligible purchases.

Merchants are assigned codes based on what they primarily sell. A purchase will not earn a higher percentage reward if the merchant’s code is not eligible. Purchases made through a third-party payment account or on an online marketplace (with multiple retailers) will not earn a higher percentage reward. A purchase may not earn a higher percentage reward if the merchant submits the purchase using a mobile or wireless card reader or if you use a mobile or digital wallet.