Why would a Leaf need supercharger access where there seems to be a growing Chademo network?...
The CHAdeMO network in USA has poor coverage in many areas. There are many places I could go in a LEAF if I could use Supercharging that I could not do on CHAdeMO itself.
There is a whole 'entitlement' / 'fairness' argument that goes into all of this. I see some signs that people think 'I paid so much for this car, that I expect exclusivity... I don't want cheapo EVs trying to use "my" charging infrastructure...'
Tesla's party line is that they are trying to bring forward the advent of electrified transportation. In the long run, this proprietary charging system could work against that goal.
CHAdeMO and SAE DC QC networks are are both far behind Superchargers in terms of deployment to good locations in the USA.
What if your Ford gas car could only fill up at Ford branded gasoline stations, or there were Cadillac brand gas stations only for Cadillacs to use?
I think the best answer in the long run is one network of standard charging stations for all EVs to be able to use.
Another thought argument is how long can a Model S be charging at a 30amp J1772 station? With such a big battery, and a J1772 adapter, I sometime find model S parked for literally all day to get a charge at a station that a car like a LEAF could have used for an hour to get back home.
I was just reading this:
Chademo Adaptor-First Use-Almost killed a leaf owner! | Forums | Tesla Motors
Where someone said : "...
you don't ever touch someone else's $100K car..." (to unplug their adapter so you can start charging.)
By calling out the price of the car it somewhat implies "it is OK for a Tesla owner (since they paid so much more) to unplug a LEAF , but not the other way around."
By providing CHAdeMO and J1772 adapters for Model S & X, Tesla suggests that it OK to use some other type of charging infrastructure, but so far, I think attempts for others to get access to Tesla standard charging has been cut off.
Is it right for a Model S to charge at a Nissan dealership?
Tesla Model S CHAdeMO Adapter In Real-World Beta Testing Phase