Moreover, I have had other businesses where the time you pay for as an employer totally matters if you're to get an ROI.
If I need you for 8 hours a day and there's an amount we've agreed on as compensation, then that's exactly what I need.
It doesn't really work if for instance it is a restaurant and you need to have waiters, dishwashers and cooks round the clock as patrons visit your establishment.
If they'd rather work fewer hours and get less money, who am I to argue? I'm just saying they'll be poorer for it and contrary to what you posited, they won't be too happy about it either.