Everyone enjoys watching their fish. That’s one reason we keep them. On the other hand, having cichlids visible in your tank because they have little to no cover might be good for you but not always good for them. This is especially true for new fish recently added to a show tank or quarantine tank.
When we confine fish in a closed environment (aquarium), we create problems for them that they wouldn’t have in the wild. Not the least of which is the inability to flee aggression/predation or to simply hide and relax. Depending on your tank set up, your fish might not be able to get away from a perceived threat (e.g., you, the cat, a tank mate). If you find your fish hiding behind a filter, a heater, a powerhead, or maybe lying on the substrate in the corner, there is a reason. Sometimes we put species together that would never be together in their respective natural environment. Sometimes species are simply incompatible.
All of the above scenarios might not mean much to you because you want to see your fish. However, there is a fine line between providing enough cover for your fish and getting to see them. Not all fish are shy, reclusive, etc. Some are naturally gregarious and readily swim out in the open.
There are hobbyists will argue that having no rocks, wood, or decorations in a tank inhibits territory establishment, which a fish can claim and defend. Others will say that overstocking will reduce aggression because no one fish is easily singled out for long periods. Trying to find that balance between offering enough shelter and not enough can be difficult. It usually comes down to experience. However, I am not a fan of overstocked tanks nor bare tanks. I personally believe these two scenarios create additional stress and inhibit the natural behaviors of most species.
Fish that want to get away, for whatever reason, but have nowhere to go will ultimately be stressed. Persistent stress facilitates physiological changes that are often detrimental. A consistently stressed fish is unlikely to remain healthy over the long term and will thus be more susceptible to illness and disease.
Good fish keepers always keeps the fishes’ well being in mind, which means putting the fishes’ well being before their own entertainment.