the terrible thing about economics is that it's very complex - "the parable of the broken window" is only a parable. the entire field of keynesian economics says that yes, you can break a window and then pay someone to fix it and increase net economic activity, as long as it's not crowding out actual economic activity that would otherwise have occurred. the "burying jars of money in the desert and paying people to dig them up" is precisely a broken window, economically speaking, and that's just a parable too.
in the real world domestic workers don't all go on to become farmers (oops that's dumped onto by subsidized western businesses too) or some other business... some degree of protectionism has consistently worked well to the extent it's arguably necessary*. And don't take this as me defending sweatshops either ;) but a moderate degree of protectionism and public investment has very consistently allowed countries to move beyond the absolute basic "we have sweatshots and scrap out old electronics and recycle garbage" stage of development. Neoliberalism and free trade will suck away any public investment you give it the opportunity to, and engineer around any comparative advantage you can find.
Keynes' point is that money stimulates economic activity, breaking deadlocks. Paying people to do useless work is only helpful because it is more socially acceptable than paying people to do no work. In no case is the useless production valuable.
In a practical sense this is pretty avoidable for the general population, however. Because you just choose something that would be useful, e.g. public works.
in the real world domestic workers don't all go on to become farmers (oops that's dumped onto by subsidized western businesses too) or some other business... some degree of protectionism has consistently worked well to the extent it's arguably necessary*. And don't take this as me defending sweatshops either ;) but a moderate degree of protectionism and public investment has very consistently allowed countries to move beyond the absolute basic "we have sweatshots and scrap out old electronics and recycle garbage" stage of development. Neoliberalism and free trade will suck away any public investment you give it the opportunity to, and engineer around any comparative advantage you can find.