Hmmm... I wonder.
Most of those shots seem to have been taken with a definitive light source.
As for 50% moonlight... if you have that under a very clear sky you do have half decent illumination. Like I said, not all NVGs of the same generation are equal. The one I used didn't hold up very well at all when it was overcast, surrounded by mountains and in a forest (all at the same time). I couldn't tell short vegetation to trail and basically had to navigate based on how the ground felt.
Gen 3 stuff seemed to hold up alright even when it looked pretty close to pitch black.
Having said that, I'm not exactly a big time NVG authority so you should ask others. Who knows, maybe there are some Gen 2 NVGs that are in fact outstanding.