It depends on the fish you keep. Some will do better with real plants because they like to browse on the algae that the plants will get. Some, like livebearers, need dense cover for their fry and a nice clump of real java moss is about the best cover you could get them. Others, like cichlids, like to arrange the decor to suit themselves and won't leave any plants where you put them anyways so for them real plants are not a good option.
I tend to have some java moss in all of my livebearer tanks and ad rooted plants to some of the tanks. In other tanks I have silk plants because they look better than the plastic ones. In a bare bottomed tank, all you really can do is leave silk or plastic plants because there is nowhere to plant a real plant.