Okay I think I missed the context regarding things that cost the property, but I'd also argue that reimbursing the destination fees or waiving parking fees does cost the property real money, no?

Imagine I'm in New York, where the destination fee is often $35 or so. That's about enough to cover an entree at the in-house restaurant. So, sure, I eat at the restaurant, order my entree, charge it to the room, and then it's wiped off the folio at checkout, but I did ultimately still pay the destination fee. If I were an Ambassador and Marriott policy was to waive destination fees, I'd effectively have cost the property $35 instead (or the property is reimbursed by corporate, is my assumption on how this works). Or pretend it's the minibar, or the laundry credit, or any multitude of things covered by the destination fees. The same goes for parking -- I think you'd be hard pressed to argue that (not) charging for parking is (not) a cost incurred by the property.

At the end of the day though, I as an elite member, especially if I were a hypothetical Ambassador, wouldn't, or rather, shouldn't care whether it's the property providing the benefit or corporate providing the benefit because as the customer, the two entities are functionally one and the same (to a layperson).