It also seems like one of those things that are near impossible to reverse if you make them the norm and things goes sideways, so I can understand they want to be cautious.
It's nice. Nobody ever does anything on Friday anyway, and a three-day weekend lets you actually go somewhere or get a project done. Moreover, when you have a weekday off regularly, you can actually go to the post office or the bank or all the other places that are only open when working people are working and can't go.
It's a little silly to only do in the summer, but it's still a nice perk.
You can see a little bit of this if you visit because you'll experience endless paperwork for everything, but this is only one layer of a very complex onion. I wouldn't say this is all bad, but it has problems.
If the results were truly as remarkable as the article is making them out to be, why not implement it all year?