I'm a mise en place hater personally, since I make a lot of things that are essentially stir fries or stews where some ingredients need significantly more time. Sure, go for it on more complicated recipes, but it's really overkill for lots of daily cooking.
I hear ya there, it’s not necessarily time-optimal when you’re not multi tasking and one step takes much longer than others. I’ll often start my onions and then go get my mise on.
But there’s something zen and satisfying about good mise.