Me and another colleague on a team of 6 have the same arrangement. Works well enough but if i worked even less then the limited exposure to the flow of relevant information would start to show. I might make up for that by declaring that i will only focus on some parts of our domain but that would make me less flexible than the rest of the team and i would feel more like a burden.

So there are parts of the world where you could reasonably go to a the day weekend if you wanted enough.

A nice side effect is that if you live in a country with progressive tax you end up getting a higher net per-hour wage than if you worked 5 days because of the lower income and thus lower tax rate.

IIUC the US has this perma-work culture where if you don't want to always be working and earning the most you can earn then something must be wrong with you, maybe you're a commie or a hippie or sth. I hear that Japan had the same but this is radically changing as a result of the pandemic. Maybe the US will change a bit too?