I know at least for California residential water use makes up just 15%. I know every little bit helps, but a toilet is an incredibly simple invention and it would be a shame to replace it with something so much more complicated.
Alternatively, just try to divert urine so it never mixes in the first place:
Both of these seem on first glance to be easier to maintain.
When I see things like "Turn a 2L bottle into a light" for a really poor area - I think awesome, something they already have laying around can make their lives way better.
When I see things like "Nano-polmer super toilet for those without running water" I just kind of shrug. Seems to cost more than adding running water, while still not providing a clean place to drink.
What am I missing?
In 3rd world locations, you can be walking 3km every 2nd day to fill a jerrycan of water.
If that's the case then you aren't going to use that to flush.
And even if you do (using grey water after cleaning etc.), then you won't have the toilet inside the house.
How much to run a line of fresh water to the house?
If <cost of toilet> is not less than <cost of fresh water line / 10>, it seems like not a win - as fresh water can solve both drinking and help with sanitation (though not get you all the way there).
Several iterations of this device might result in something very useful in areas far away from the ocean (which makes desalination difference), and lacking the major infrastructure for centralized water recycling.
Why do we need to build such a fancy and complicated device when all you need is to pee in a separate bucket from your poo, and let the poo aerate/dry naturally? Mix in some dry mulch and you're done!
Urine itself is sterile and can be easily treated/recycled.
This is a misconception that particularly annoys me, probably because it was the (incorrect) excuse a nurse once gave me when he accidentally spilled a urinal filled with liquid all over me while I was bed-ridden in an ICU.  
he accidentally spilled a urinal filled with liquid all over me while I was bed-ridden in an ICU.  
My late father recently developed a waterless toilet which is significantly simpler and likely cheaper than this one.
However, the one in the video seems more geared at sustainability and reuse. They filter the water out of the pee. Dry out the poo for fertilisation.
Then again living in the USA has accustomed me to commercials which represent female menses with water, dyed light blue.
If there really are developing areas who fail in this design principle, they need education on how to design their food production. Holding back a useful tool just because some people might use it incorrectly doesn't make sense. But most people who are even somewhat self-sufficient know that the flow of water is a crucial design point.
If not composted and used productively, then human waste is just a pollutant. But if you can increase food production and have a productive recycling of materials at the same time, you are killing two birds with one stone.
I often wonder about the cost of toilets on large scale.
Also, I'm assuming the toilet will go up in price as more people try to make more off the system.
All that said, I welcome the Nano Membrane toilet to the much needed market. I'm all for composting toilet technology as our current system of simply creating raw sewage then trying to treat it with massive amounts of chemicals (which are very bad for the environment) isn't sustainable.
1) Natureshead, 2) Airhead, and 3) Separett toilet
These three all much better suited to low cost, rural uses. For more hi-tech versions we have Sun-Mar. However, all these still cost at least $1,000 USD.
Plus they have a limited lifetime; they fill up, and you need to dig a new one.
Feces compost just fine in a dry environment, if you mix it with enough carbon (dried plants or sawdust). No treatment, except letting it decompose over a couple of years, and very little smell if the nitrate/carbon/humidity balance is respected.
Of course, water companies wouldn't be thrilled by such a simplification, and people like the illusion that their poo-poo just magically disappears when they press a button.