A question about process and a novel-length story

My latest writing project is a novel. There. I said it. I have been working on it for over a month, and it concerns a topic that's been intriguing me since 2003, that's about all I will say about its content. As for the process of this writing project, I find myself doing something I've never done before: saving drafts as I go

That is, after writing several thousand words, I save the document with a "save point" appended to the filename. I also save the document with its original filename, and then I get back to working in that document. Basically, once every week or so, I go through this:

Open "filename"
Writewritewritewrite.
Me: Okay, Marshall. You've been drafting and futzing around for a week. It's time to make a save point.
Go to File, Choose "Save as"... type "filename--save point 1." 
Go to File, Choose "Save as..." type filename." 
Computer: "You already have a file called "filename." Overwrite?"
Me: YES!
Computer: Ok. Saving. Done.
Back to writing. 
Writewritewritewrite.
Done writing for the day: Save.

The "save point" figuratively preserves the draft in amber, while I keep working on the novel. At this point, I have four "save points" that reveal how the novel has progressed--and changed--over the past month. I have removed portions of the novel, added portions of the novel; and I have also adjusted portions of the novel to better reflect my goals for the project.

Why not use MS Word's "track changes" feature? I thought that it might look kind of messy. In my draft, I have the entire arc of the story roughly puzzled out, but sometimes that puzzle changes dramatically; pieces appear and disappear, or shift from the outside to the inisde or vice-versa. At some point in the future, I would like to see the draft as it unfolded. I would rather scroll through these save points as whole artifacts that were, in their time, a representation of the story as it was.

I guess, in some way, I hope that these drafts might serve as artifacts I can study to learn more about my own process--and perhaps as teaching tools for others. I wonder. I also wonder if I'm alone in doing this.