As per HDFC Bank's terms and conditions for the Tata Neu Infinity credit card:
"A cardholder will not be eligible for NeuCoins on prepaid card/gift Card/ wallet load and / or voucher
purchases. i.e., the transactions carried out through the Merchant Category Code (MCC) of 6540 (as defined by
card networks Visa, MasterCard and RuPay) will be not considered for NeuCoins."
However, the gift card purchase I did at Tata Neu has the MCC 7311 (Advertising) and shows as "Tata Digital" in the statement.
Since Advertising is not excluded from getting rewards, it would surely earn rewards in some form. And most likely, it will earn 5%, as it's also mentioned in the Tata Neu app during checkout.