A more "economically neutral" perspective (not that I claim it is a better perspective) is that there is labor that this particular human has available. Letting them choose to spend it on hunting down a sale is strictly better than removing that choice. There may be "better" things they could do with it according to you, but ultimately it should be their choice.

The irony is particulary deep here because hunting down a sale is surely no less wasteful to society than actually playing Factorio which is a pointless videogame famous for being an addictive time-sink. If the goal was to maximize societal benefit, we'd remove Factorio from the market entirely.

> If we want poorer people to have better access to the goods and services richer people buy, we should just give them more money.

I think you're jumping to a conclusion that these people are particularly poor. But my only claim is that people have different relative distributions of money versus time, and that is probably true at all wealth levels. There are both idle rich and workaholics. There are poor folks working three jobs and raising three kids and others that are couch potatoes.

Sales are a way to let consumers at any economic level reflect their relative priority between time and cash.