This is a very different approach. The google approach is making an airplane fly in circles generating continuous power, this slowly lets a kite out then reels it in generating pulsed power that would need a battery to smooth out. This approach can use pretty standard kite technology which is far cheaper than airplane technology.
Use multiple kites in a staggered pattern so one of them is always generating near peak power. That complexity of course offsets all of the gains, but that's fine because it illustrates why this is an idea that just won't fly.
Batteries are fine, the majority of the time it'll be in the pull stage as once depowered (the power is taken out of the kite by releasing the brake lines) you can bring the kite back down pretty quickly. Having two with the cycles staggered would reduce this but you need batteries anyway because you can't rely on demand being flat.
The algorithms to control the kite are pretty straightforward, the complexity to self launch would be a bit tough but it's easy enough for a human to do so there is no need to include that complexity for the use cases this is targeting. This wouldn't be a set and forget solution, not yet.
The kites will wear out relatively quickly but they're cheap to replace.
I consider myself a pretty skeptical / practical Engineer and I don't see any show stoppers, I think it'll fit the niche they're targeting quite nicely.
From both a maintenance, operational cost and engineering complexity point of view I don't see this as viable, but I'm more than happy to be proven wrong by a party that brings it successfully to market. Meanwhile, any place where this kite system would work is one where a regular HAT would work as well and long term (25 year lifespan) total cost of ownership and $/KWh generated will be pretty easy to determine by deploying two systems side-by-side.
