Imagine putting your tongue on the charging plug

Spread it over enough people and it's the same energy. For one person it's a much shorter charge. Over a population with random charging times it's the same consumption off the grid. The problem then becomes a distribution issue, not a production issue.

Likely these kind of chargers will be expensive and at supercharge stations. Homes will use lower over longer.periods as it's rare you want to pop home for 10 minutes needing a full charge.

This is a big step forward, no matter how you look at it.

It might be also useful for excess storage when we have wind and solar energy that the grid doesnt need. Being able to do so rapidly will mean a smaller array of batteries required for grod storage.

I'm not sure people are going to be interested in paying for megawatt-capable chargers, anyway. There's a couple of sites near me that have old 50 kW chargers and new 250 kW chargers, and have higher prices on the 250s. I expect that sort of thing to continue - providers are going to want to cover their costs and higher powered chargers are more expensive to buy and operate.

Assuming efficiency of ~4 miles per kWh (on the high end of current EV efficiency)

Why should we assume this?

I'm getting close to 8m/kwh on the high-end. Realistically, I'm ranging between 3.6 to 5 m/kwh. But when I drove for Uber, I did 200 miles using only 34.1 kwh, I drove slow, and it was mostly city driving. So I could only need 137 kwh for 800 miles. Still prohibitively unrealistic to charge in 10 minutes. It's about 1.4 MWatts to charge from empty for 10 minutes.

the charge power needed for the 200KWH is not 1.2 MWatts for 10 minutes, it's 2MWatts. Mostly because you can only charge fast at lower percentage.

That would be impractical even for fleet vehicles.

Unless they're also going to announce the development of nuclear fusion in order to provide the necessary cheap energy, then I don't think this is going anywhere.