The article says "per hour", not per day. Although that would seem able to support dozens of users rather than just 1.
I'm a little confused then, later in the article it says "The team estimates that a system with a roughly 1-square-meter solar collecting area could meet the daily drinking water needs of one person." So something doesn't add up.
[Edit: the paper is available at https://pubs.rsc.org/en/content/articlehtml/2020/ee/c9ee0412.... It says, "To meet the average daily water intake for one adult (≈3.2 L),49 100 TMSS devices can be placed into a 10 × 10 array, filling an 1 m2 area, which would provide approximately 10–20 L of clean water every day depending on the weather condition."
The lower bound of 10l is outdoor performance on a partly sunny day. So I think they are just being conservative by saying it would meet the requirements of one person - coastal areas are frequently cloudy, and in some locations, there might be little sun for extended periods of time.]
And actually it does seem like 'drinking water' is actually drinking water and not for all those other uses you mentioned. As 3.7 litres is the amount required for a human male each day.
https://www.mayoclinic.org/healthy-lifestyle/nutrition-and-h...
Are you suggesting that toilets, showers, washing machines use salt water?
It would be an interesting experiment, since toilets use a great deal of water. Take a beach town, build a separate pressure water and sewer system, see if it's worth it. It's certainly more complicated than a sailboat's set up.
> Drinking water, also known as potable water, is water that is safe to drink or use for food preparation.
40-50L per day would seem to about cover one person's essential uses of potable water.
[1] https://www.usgs.gov/special-topic/water-science-school/scie...