If I have to spend time creating awesome marketing content, why would I want to publish it and have it disappear in a few days? If I follow Target, they can offer me toothpaste this week and cheap sandals the next week. If I'm interested in this brand, I'll follow them to see what this week's deal is. We sell a specific product that people want when they want it. On the surface, you might say, well, if I keep giving them special offers and other photo ideas on something like SnapChat, eventually they might decide to buy. The problem with the logic is that if they aren't in the market for photography now, they will most likely decide to unfollow you long before they decide to do so.