Isn't it depends on our travel requirement?
Correct me even if I say one transfer partner which allows you to transfer 7 different partners, but none of those properties/airlines covers or need for your travel plan, then its useless to store points there, right?
If a person has only domestic travel planned in coming year then even though not much further transfers CV is the best option because teansfering to international airlines (which you maybe further transfer to multiple other international airlines based on destination) doesnt serve any purpose, IMO.