The battery swap feature was implemented only to maximize California clean energy credits. Only enough infrastructure was built to claim the credits.
“In 2013, California revised its Zero Emissions Vehicle credit system so that long-range ZEVs that were able to charge 80% in under 15 minutes earned almost twice as many credits as those that didn’t. Overnight, Tesla’s 85 kWh Model S went from earning four credits per vehicle to seven. Moreover, to earn this dramatic increase in credits, Tesla needed to prove to CARB that such rapid refueling events were possible. By demonstrating battery swap on just one vehicle, Tesla nearly doubled the ZEV credits earned by its entire fleet even if none of them actually used the swap capability.”
“In 2013, California revised its Zero Emissions Vehicle credit system so that long-range ZEVs that were able to charge 80% in under 15 minutes earned almost twice as many credits as those that didn’t. Overnight, Tesla’s 85 kWh Model S went from earning four credits per vehicle to seven. Moreover, to earn this dramatic increase in credits, Tesla needed to prove to CARB that such rapid refueling events were possible. By demonstrating battery swap on just one vehicle, Tesla nearly doubled the ZEV credits earned by its entire fleet even if none of them actually used the swap capability.”