It is a modest trial of a four day work week. You are so far from disaster. This can only be a good thing, if it doesn't work they stop doing it, but probably it will work because people are more productive when they have time to breath.
Spaniards don’t appreciate research, we only nod when solutions sprout out of the blue.
In fact, less work hours will be a complication for many -as they are used to justify the work done by sitting for extra-hours at their desk. It’s sad, but it’s also my daily routine.