Maybe I've overlooked something but the advantage over photo period seem to be it is easier, not having to deal with light cycles and a predictible finish date if the supplier is accurate,you could get a grow with autos in before sexing photos,but photo you now have clones so you make up time (but it is more involved and perhaps it's not an option so that makes sense). Now photos are head to head and some photo strains will beat an auto from clone in flowering,so the time you initially gained now you will keep losing as the clones will grow into monsters the following year for outdoor use as well, easily out producing any auto. Obviously this is for people who also grow indoors for preservation,people get offended and that's crazy,I couldn't care less if someone told me photos sucked,I'll grow what works for me and my situation,it's just a debate.