Tesla sells a good number of S and X models that are used. People still buy used Leafs and some of those were notorious for battery issues. Unlike Nissan Tesla packs are liquid cooled and managed. So for the most part what many have to move on from is the stereotype incurred by one brand having battery longevity issues affecting the perception of the industry.
However I think it is a good idea to state they have a use for the off lease cars which gives them an out with having to expense new vehicles for such a risk venture; I am not a believer in anyone's autonomy programs.
Also, lots of cars come off lease with under 50k miles on it, so no reason to think the car would just be discounted by the relatively small amount of lowered battery capacity at this mileage.
Battery degradation is largely a matter of use + thermal management. Since cars have thermal control systems installed (unlike your phone), you should expect a car battery to last a lot longer than a cell phone does.
