7200V will jump an arc approximately 1". I played with neon transformers when I was young. Very cool, but bite you easily!
Here's what I learned working with electricity as an electrician: 120V hurts like hell and can kill you if you touch it. 220V is similar, you need to touch it. By the time you get to 480V you don't have to touch it-it comes looking for you. 7200V at the current levels required (still talking 22+ amps, so need wire for 30 Amps) will have to have a heck of an insulator and be rigorously inspected and worked to keep safe. Not to mention the connectors.
Also, if you step it up on the charger side to reduce current and wire sizes you have to step it back down before the batteries. That's added stuff on the car. And very high current carrying step down circuitry. (BIG heat sinks.)
And you haven't addressed getting the electricity to the charging stations.
I'm not saying it can't be solved, but the sheer amount of energy required is seldom discussed with these cars.
I'm supervising a backup power system for our current office building. ~24,000 square feet, lots of computers (and therefore lots of A/C). We're buying and installing a 120kVA generator. That's just enough to charge a Tesla (roadster, based on above examples) in 45 minutes. That will run our whole building. Now triple that, (gets the charge time down to 15 minutes) then multiply by 12 or 20 to build a full up Flying J style electric car stop on the highway. I get 7.2 million VA (or megawatts). That's a huge amount of power for a "gas station". However you deliver the power in terms of voltage and current, it's still a lot of electrons.
I
John