Makes sense to me. For most of my 40+ years of working, I worked a 32 hour work week and this was mostly for large corporations. I simply informed HR that I would not be working Monday's and to pay me 80% of my salary. It always amazed me that I was able to do this decade after decade, but the trick was that I worked really hard the 4 days I was in the office.
I mostly used the extra time for friends and family, and to write books.
BTW if you went around and asked a bunch of software engineers how they finangled there way into working a sub-40 week and collected that into a e-book. I would buy the shit out of that. And judging from other hacker news posts there are lots of other developers who would as well.
I would do it myself but I don't have the extra day to write books :) and I'm a terrible writer.
I mostly used the extra time for friends and family, and to write books.