Seems like the value prop is if you have 8-10 people and want a house. At least in my initial searches, Marriott doesn't have nearly the inventory that Airbnb and Booking.com have for 1- or 2-bedroom apartments. (It's possible I'm not looking at the right cities I guess...)

The houses I've seen look fantastic. Certainly not the most cost-effective way to simply top off a status run, but if you have a few people and want to do a stay somewhere that's much more memorable than booking a bunch of hotel rooms, I'd say go for it.

When we do family trips these days (total of up to 10 people), booking a house is definitely my preferred way to go. One of these days I'll do it through Marriott. I've added it to my search list. Hope it has traction and attracts more properties.