Your comment (point 2 especially) reflects the current widespread notion (among employers at least, it seems) that one hour of work is one hour of work, always. I think the main point of the article is exactly to counter that.

> "Productivity – output per working hour – improves with shorter hours."

And why should the employer get all the benefit from this? I think a lot of people would love to work fewer hours, be more productive those hours, if they could retain the same salary.

I would love to, at least, but can't afford reduced pay.