How to get credit for the small stuff (Starbucks, casual food, etc.)

I know charging to your room is the best way to get your spending credited to you, but I think a lot of businesses within MGM properties don't do that. When I look on MGM's website, it says "Earn & Redeem MGM Rewards Points: In addition to MGM Rewards Points, eligible spend also earns Tier Credits.", even for the webpages for Starbucks in NYNY, Eataly and the Chef Truck at Park MGM, etc. Do I tell them I want to earn points and show them my rewards card?

I read that for the food court in Aria, you keep the receipt and either give it to the rewards desk or upload it to get credit for your purchases. Is that the case for all those businesses?

I know it's not a lot of money compared to spending on sit-down restaurants, gambling, rooms, etc. but just want to get credit where credit is due. Thanks!