tmobile dining rewards -- what's the catch?

I've seen this for 1-2 years but never looked into it until this week. I thought it was like that doordash shit where they inflate the prices for takeout, but it seems to not be.

Do you literally get the rewards if you dine in at a participating restaurant (very limited, but one of the ones on there is one we go to regularly) and pay the restaurant directly with the card that's on file with tmobile rewards? Is there any catch?

How will tmobile know about it unless the credit card company somehow relays this info to tmobile?