More accurately, that's the amount of power the charger supplied over that time.
What matters more is the amount of battery charge gained. The battery charged from 10 to 80% SoC in 20 minutes, which is 87 EPA miles (140km). That's charging at a rate of 260 miles range per hour (419 km per hour), EPA.
These numbers are consistent with, or even slightly ahead of, Hyundai's marketing materials that promise 24 minutes for a 0-80% SoC charge, or 248 mile range per hour.
If we assume the constant current phase ends at a battery voltage around 395V, the peak of 69.3kW implies a max DC fast charge current of 175A [69300/395].
Good point on the charging gained and that's something i'll be tracking as time goes on and these batteries get more usage. A battery that's going bad won't hold a charge as well, it will lose that power quicker than a battery that's healthy and operating how it should. Really hope the turnover for these is long enough. 6-7 years seems good to me.