The team doesn't work Fridays. Even if in other roles you can get by with < 40 hours, you'll be hard pressed to fully disconnect from work on Fridays. Having clear 3-days weekends every week is much nicer than just trying to take it easy but being available all 5 days, IMO.

That said, in the nominally-40hr roles you won't get paid less, so YMMV on what's better