Years ago, I scorned the feather duster as laziness, not to mention that you're just knocking down the dust, to have it mess up the floor. But now I see things differently.
A real duster made of feather isn't as good as this thing made of - filaments, you could call them - and when I don't have much time I can, yes, knock the dust on the floor. And then, mop it up. It's way better than nothing.