its not usually. For some reason the images don't come across sometimes for photobucket hosted pictures on the mouse over. The bandwidth exceeded issue doesn't effect most people, especially if you keep your images at 800x600 which for most forums is the perfect size anyways. To each their own, but the simplicity of photobucket and the fact they provide you with virtually any link for your images for any type of website is very helpful. The user interface is idiot proof (important to me) and its fast. It also has built in image editors which can be used to blur license plates, faces, etc.
But that's enough good reasons, I don't get paid for this so I'll stop. :)