A popular use of such grow-lights is for growing, er, "pot plants" in ones wardrobe. Hence the "one's personal use" phrase. But they do work just as well for other plants, assuming that the plants actually want the light, which many of them do. People commonly use them for growing plants indoors or at high latitudes that like high light intensity and/or specific day-lengths, such as early season development of tomato and chilli plants. Growlights are specially designed fluorescents. Fluorescents put out a lot of light without putting out the heat that would cook the plants. But many tight-wads just use ordinary fluorescent tubes, which are considerably better than nothing. Have a look around some chilli-head sites such as www.fatalii.net (a chilli grower in light-deficient Finland).