Amazon seems to be the only place which sells any gift cards which would count as online and retail. I've searched a few other online retailers and they all seem to use a third party for most of their gift cards which would classify as something different.

If you purchase all 5 x $200 in one transaction it might work? The egift card shows as being sold by Amazon.com while the physical gift card shows as being sold by Amazon Payments, Inc.

I wonder how the merchant code works for Amazon since Amazon has 1. third party sellers who ship from Amazon 2. gift cards which are sold by "ACI Gift Cards LLC, an Amazon company", "Amazon.com" or "Amazon Payments, Inc". and 3. third party sellers who do not ship from Amazon

Here's the definition for retail purchases

Retail purchases are transactions made at men & women’s clothing stores, sports and riding apparel stores, shoe stores, accessory and apparel stores, music stores, computer software stores, sporting goods stores, book stores, office/school supply and stationery stores, game/toy and hobby shops, camera and photographic supply stores, card/gift/novelty and souvenir shops, leather goods and luggage stores, artist supply stores/craft shops, art dealers and galleries, cosmetic stores, florists, pet shops, pet food and supplies, swimming pools sales and supplies, duty free stores, discount stores, department stores, variety stores and miscellaneous general merchandise stores. Purchases not eligible for this offer include purchases made at home improvement stores, wholesale clubs, grocery stores or special events.