The bigger why.
Because I have a keyboard itch. Writing is my habit. Once I gave up on writing SF stories, late 2003, I was tinkering with zod as an editor, in which I'd write more, even started turning the last story into a novel. But it ended up as a small heap of loose dialogs in still unconnected episodes... and then I realized I'd never finish it. Because the economy. Serious writing requires the means to live through it, and at the time we had two daughters at the university, a mortgage on top of that, and I was losing jobs periodically. Everything but the spare time. And the small stuff, stories, I considered just expanded pieces of wit, for which I lacked the will.
For a while an idea percolated through my mind, that SF could be written as hypertext - which I initially imagined structured as a help system, like the one on the Vaha, which wasn't a true hypertext but each article had a list of related articles beneath itself, and you could pick one, go back etc (so it was before Pavić's Hazar dictionary, at least before I heard of it). Which I actually put in several of my stories, and one has actual internal hyperlinks in it, as I wrote it interlinked from day one. Web edition is the only edition.
There were a few more ideas runnin, see Byo, and so I started this. And I liked doing it, the so-called research was already done, I had the material at hand, it was easy to do, even with the structure of the material being often loose, so ordering it by date was due, but hey, I'm a programmer, I can do that.
Now writing this for fifteen years and counting, fuckit, I'm stubborn and won't give up, I'm already doing sGradlj.com like that for more than 20 years, and still am not bored with it. That's, I guess, the nature of programmer's work, it's never finished when it's finished, it's finished when you stop working on it, but then maybe you'll return it to do some more. I'm used to things that work but may need a few touches here and there, ad infinitum, I don't feel it as a chore.
And, as I said in 15-VII-2022., an autobiography is, by definition, unfinished.