Paraphrasing a bit from the scientific source:

If the population of Canada used email signatures for a year, ~30 people in developing countries will suffer a premature death within the next 100 years.

That 100% should have been in the article in some clear form or another.

I’m not against the points of the article, I’m against it being so poorly written that AI slop is just as good.

This is AI slop.

This really depends on your tap water; in some places tap water is clean enough to work, but it seems yours is not. If you want something to just set and forget, you’ll probably need to do more localised research. E.g Hardness, turbidity, etc.