I’ve charged in 30 states, it’s kwh every single time.

Mowt states have changed the laws in the past 10 years. When nobody (other that lead acid convestions done at home) had an ev it did't matter that the law didn't allow for charging by kwh as nobody other than a utility wanted to do that anyway. When evs changed to mainstream laws changed. There are still some free public chargers near me from before the law change (at 6kw max charge rate they not often used and so don't cost them much to keep it.