The internet is a constant changing place. There are always new and improved ways to do things. Update and maintenance are never-ending tasks that must be done. Writing descriptions and adding ALT tags for smaller websites with fewer images are less of a concern and is not that bad of an undertaking. However, when you run a big retail website with a lot of images and other elements, tracking down all the ALT tags and adding descriptions to make updates can be a nightmare for any webmaster.