The main thing that separates speed walking ("race walking") from running is that you must always have a point of contact with the ground.

That said, I've seen some articles of high speed video taken of pro race walkers and basically all of them have tiny moments where both feet are off the ground. Just not egregious enough for a referee to detect.

In general, seems like a really contrived sport, but to each his own...

$1400 doesn't seem that bad for the very first product of this type compared to other e-mobility stuff. E-bikes can cost around that price point (and way more of course) and they're a mature category. Scooters are much cheaper of course, but again, this is the first product of this type.

I think it's technically walking as long as one foot is always on the ground.

As long as both feet aren't in the air at the same time it's walking.