In a similar vein on skyrim, what’s the point of having merchants have limited money when fast travel/wait is a thing?

All it does is make me spend 10 minutes fast traveling to all the towns to sell my stupid dragon bones. What does that even add? It doesn’t add difficulty or immersion. Because of the dumb encumbrance, I can’t continue playing the game until I sell all this crap, so I gotta deal with it sooner or later.