I don't do this so I don't have a dog in the fight, so you use your CC to buy Walmart gift cards at face value..Then you use the gift cards to buy a money order which apparently is OK with Walmart. All the CC company knows is that you spent money at Wal-mart...what you do with those cards is your business..I'm not agreeing this is "questionable"..in fact who loses from it. You might say Wal-mart since you didn't buy anything from them..but WalMart sets the rules for the use of gift cards.Wal-mart does get a fee for doing the money order.
CC company does not like this. They are the loser in this game when card holder did not really spend the money, because they now need to pay out the bonus. In the case of Chase Sapphire Reserve card, the bonus is worth more than $1,200 dollars with 100K points.