autoflowers alow growers to run a perpetual garden with 1 room and 1 light... sum ppl dont have the $, time, space, know how/care for, or effort to clone and run a 2 room perpetual... not to mention legalities... if a person is alowed 6 plants at a time, its gonna be hard to stay in that plant # when u got clones, veggers, and flowers so autos will allow them to harvest perpetually with out goin over... u can also start them early inside and put them outside to harvest mid summer and avoid cops and robbers... whos gonna be looking for pot plants in the bush late july??
as far as the photo part, plants need sleep.. they produce food in the light and use it in the dark... if u run 16hrs light and 24 hrs light, the 16hrs will be lrger cuz they will stretch in the dark... 1 reason tey do that big stretch in the first few weeks of 12/12