Look above. Another poster madec same point. The miles youre getting here are from the company you're booking with. In this case Delta. Just like when you book with Orbitz, you earn Orbucks. In that case the hotel isn't the one giving the Orbucks, Orbitz is. In the case here, it gets confusing because you can have
1)the miles Delta is awarding for booking the hotel through them and
2)the miles (if any) the hotel awards for staying.

Notice one is for booking, while the later is for staying.

You need yo be clear you're asking for miles from booking a service through Delta. You're not asking for miles for staying at a hotel.