Does the comment on Page 6 "There are no direct-coupled lighting systems ...." only pertain to residential lights?
Wouldn't the 12v lights in some RVs be considered a direct-coupled lighting system?
A direct coupled or direct PV system has no batteries or energy storage, so the reason that a lighting system does not make sense, is that the lights would only work when the sun is out. I'm sure it has been done, it is just not practical, unless you live in a cave and want to keep your circadian rhythms the same as those surface dwellers.
I was doing a site survey at an orphanage in Lebanon and the person in charge wanted to have a direct lighting system and they said that school would only happen when it was light anyway. It could be done, but it would be a more effective use of PV to connect to the grid, turn the lights off on the weekend and when people were not in the room and have extra energy to spare, with a light that would work at night if needed.