What marketers sell is hope.
The reason is simple: people need more. We run out. We need it replenished. Hope is almost always in short supply.
The magical thing about selling hope is that it makes everything else work better, every day get better, every project work better, every relationship feel better. If you can actually deliver on the hope you sell, there will be a line out the door.
Hope cures cynicism. Hope increases productivity. Hope needs no justification.