They're an absolute boon to Web designers where different stakeholders in the client organisation can't make up their bloody minds. There comes a snapping point where a carousel is suggested to avoid insanity.
Indeed. It's an organizational relief valve that doesn't rock the boat much from a UI or product perspective. This is less of a problem at a small company, but a big problem at large companies. Standardizing the creative unit also makes it much easier to manage, and can be changed quickly by a semi-technical person if they are given a tool.