Swapping does help reduce the high peak power demands that fast charging has. There's limited places where you can get the infrastructure to install a bank of chargers capable of this kind of speed (though, one potential approach is having a local block of batteries near the charger, but you are then paying the efficiency cost of another battery round-trip, and the cost of the batteries which will get a lot of wear and tear themselves)

But if you need batteries that gives you the opportunity to install solar and reduce your costs more than the efficiency hit.