with low light performance of the 5n, what is the appeal of full-frame?

I guess I don't think I'll do it with any shot I take purposefully, but I like having the option when I get ones that I really, really like . . . like this one I put up last week:

I'd rather keep my options open than close them off completely just because I don't print this size often. That being said, I was able to accomplish this with my 5N so there's that, too.

I don't even think it needs to be a pro versus amateur issue . . . some of us enjoy the hobby enough to just want the best quality we can afford. I gain great satisfaction in being able to shoot the image that I visualize in my head when setting up a shot even if most of my photos are just being posted to Flickr.