Thanks to Redneck Justin for sending this my way.
It’s probably not a valuable enough deal to just buy the tires for the free nights, though I guess some industrious soul might buy tires and then sell them on eBay.
Part of what makes it a bit less valuable is that the Ritz hotels are excluded along with a bunch of other top-tier properties. It took a bit of digging, but the full list of participating hotels is here. It’s only 2700 of about 4000 hotels total, so there are a LOT not participating.
Admittedly, I’m not a Marriott guy, so I’m a bit biased against the value of their mid-tier properties. But, if you’re already in the market for tires, it wouldn’t be too hard to get $200-$400 value out of two weekend nights at some of the properties on the list.