To be fair, his hairline does not look unnatural. It just looks too low aesthetically due to proportions. He could easily have had a NW0 hairline a bit higher up, and it would look great. This photo is not a good example of "NW0 is bad", but of "he went too low based on facial proportions".
I'll chime in to what most people here already said. If you have progressive balding, you probably can't afford the grafts to go back to full NW0, as it's simply too many. You don't have infinite donor.
If on the other hand, you're similar to me, and have no balding, go for it. Just make sure you have a good surgeon. To get a NW0 look, you usually need temporal work, and that is very hard to do. Most surgeons will leave you looking like a clown as they're simply not good enough for temporal peaks.
I had mine done, and the result is great, but be careful and make sure you do your research when contemplating it.