Well, actually, that is not strictly right...They do need more and they also require a very mature aquarium, which your is not. Just because you have one in your system, does not make it correct for anyone else to do the same. Nems are fabulous beautifull things and should not be treated like a $5 tetra..
You are talking about something that has the potential to out live "You" as a human. How do you know that it is doing well under that ammount of lighting? Something that lives and grows so slowly also has the potential to grow poorly very slowly aswell, like growing poorly over a period of years..
Niko