If it's attractive enough, I will most certainly use it.
Being able to pay my £1k Avis SUV summer holiday rental bill in the US with Avios points would be a big benefit. BUT, if it's not in line with the value my Avios points are worth to me on flights in a premium cabin, I'm not going to bother.
Let's hope it represents good value. And then it will be a massively popular upgrade to the Club.
I presume Avis will be the partner of choice for rental (it should be, surely). And it would be good to see a spread of hotel chains, from mid-range motel types (i.e. Holiday Inn Express etc), right up to the luxury places.