But that is exactly the issue, unless there is something hidden regarding events or quests spawning based on who you sell your merchandise to, the effects of this change is quite small, it would only affects what kind of merchandise you decide to sell, and once you figure out which ones are more valuable to sell, you will stick to these.
Not to mention being weird overall, not the appearance, but how it affects the game, if you keep changing the entire decoration of the shop from one day to the other based on what kind of stuff you want to sell, like, flipping the appearance of the shop from rich to poor, so that it magically makes people cities far away finding out that yesterday the shop looked like it housed the British Royal Wedding so that you would attract nobles as customers, and now it looks like a scene from slumdog millionaire so you can sell the rest of your stuff to poor people, It may look like something interesting when you are just observing it, but being able to change it entirely and have it's effects show up immediately is at least weird, unless you balance it by implementing some sort of reputation built over time for every 'faction' of customer