What it does do is shore up demand, which is why all those products got made in the first place. They got made because someone had an expectation that they could sell them. Nobody is going to be making anything to sell if the entire population has no money.

This is why it's essential that relief go to directly to people, and that we free those people up enough from expenses that aren't directly economically productive (things like rent, say) as we can. We want people to have money to spend, so producers will have a reason to go on making things to sell them.