I think its because I'm really enjoying this piece and I like seeing it progress. I imagine other people would have an interest in seeing the process too.
Also stopping and taking pictures gives me a chance to see what needs changing so I can go a head an fix it before I commit too much ink and time to it.
For example, I have changed the hand but now I have noticed that the fingers on the hands need to be slightly more slender, and the neck needs to be changed as its not in the correct place.
So in the next update I probably would have made these changes.
I'm already starting to get a little bit crazy from doing all the hair detail. There is still so much to do! It's going to look soooo good!