Because this lens simply "paints" like no other one I've used. I almost sold my chrome one before (size), and now am relieved that the sale didn't go through! As stated, I simply got a smaller 35 to take around when the 1.2 was too hefty, but when you don't mind taking it out, the 1.2 will surely satisfy.
I think I saw a video recently with Eggleston using one.
Some of my samples:
[IG]http://farm3.static.flickr.com/2214/2418039330_a26d34bbb7.jpg[/IMG]
[IG]http://farm4.static.flickr.com/3097/3130814400_ce28d1719d.jpg[/IMG]
[IG]http://farm4.static.flickr.com/3111/2377913241_5fbc1218dd.jpg[/IMG]