[sonnyblarney]

"It would be like saying you have a healthy relationship with smoking because you don't smoke at all for one day a week, but after that you can chain smoke 24/6."

What?

No.

You need food, but you can overeat.

You need exercise, but you can do too much.

It's not an irrational argument to indicate we need a day off, moreover, it's not irrational to suggest we do it at the same time.

FYI - have a look at your activity logs. Whatever business you're in, I'll bet a lot that it's down on Sunday. All our charts show a huge drop them. So we already are a little bit conditioned for this behaviour. It's worth considering nudging in a given direction.