After looking at this some more after we talked about it, I'm kinda "meh" on it. The video's kind of goofy, calling it 'revolutionary' - it's just a dehumidifier with a UV and charcoal water filter bolted on. For $800!
Just buy a normal, large dehumidifier, another of the 3-stage water filters we're already using, and another cheap sump pump; have the sump pump push water through the filter every time the reservoir gets above some line and run the filter line straight into the fresh tank. I bet you could do all that for like $300, and it's a trivial installation.
The bigger problem is, that's a lot of electricity. My situation is a bit tricky right now because in Seattle, the time of year when humidity is an issue is also the time the days are short and dark.
Right now there are days, multiple days in a row where I get maybe 12ah total back in the batteries during the day - we may only have ~6 hours of what you could call "light" and the panels are running at basically 4% of max wattage. Yeah, it gets really really gray here. That's 5% of my batteries refilling, and even trying to be extremely conservative I use ~20% a day, just running the fridge and vent fan to keep the humidity from decimating me.
You noted there's a ~80W version of this you found that does 1 gal a day, but that's 160ah a day at 12V, which is 62% of my battery capacity (258ah total) every day. And a gallon of water a day is already a relatively spartan shower. If I ran it for 25% of that time I'd get a quart of water a day (or a bit less since it takes a while to get going) for 16% of my battery capacity daily, which I still can't afford right now, not even close.
I think this may make a lot of sense if you have shore power. But that's a big 'if' - if I had shore power essentially all my constraints would vanish.
And even then, it's still just a dehumidifier run through a Brita filter... you can do this for cheap, and much more compact.