Not OP but I see it for many different types of items. Think bandages, ankle wraps, mouth wash, antacids, OTC pain relievers, etc. You might say that antacids

Not OP but I see it for many different types of items. Think bandages, ankle wraps, mouth wash, antacids, OTC pain relievers, etc. You might say that antacids and OTC pain relievers are drugs, and that's fair. But there are other concerns besides the active ingredients. For example, I might prefer the taste of Tums to CVS brand. Or for a personally-true example, I used to find the CVS brand ibuprofen gelcaps to have a funny, sour smell that I didn't notice with Advil. (I don't notice that anymore.) Or my grandmother used to buy a specific brand of some contact lens cleaner (can't remember which), because she found the top much easier to open. The point is it's not always about the efficacy of the drug; sometimes it's about the overall experience.