I also can't imagine who pays for unlimited beside someone who has ALOT of stays,so that 4 instead of 5 stays get a free night becomes valuable (like 20 stays or so a year) or the person could save on the airport transfers as he/she would pay for that out of their own pocket anyways...
Losing the upgrade at the time of booking doesnt make it more attractive...
On the other side wouldn't call 8 hotels in London a "very limited coverage"