There are so many reasons to partake in underwater photography. If your first love is diving and the underwater world, then capturing photographic memories of your dives and those people you dive with will allow you to remember those dives forever and share your experiences with others. Capturing photographs of corals, sponges, fish, sharks, whales, and other marine life is fun and you will truly appreciate having the visual memory of these wonders of the ocean.
You may also be an amateur or professional photographer or have aspirations to become one. In fact, maybe that's why you got your diver's certification in the first place, so that you could photograph the underwater world. If you have dreams of becoming an amateur or professional underwater photographer, then training for it is crucial.