I've seen the term many times before in context I found appealing, but the wiki page talks mainly about the connection to actual music.
And then there's the real 'theoretical' music theory, which does what you might expect: theorizes how music works. What is music? What makes music good? What makes a particular song 'tick'? This can get pretty abstract, and might involve some nifty math. Still not strictly scientific, though there may be some science involved.
If you have a theory as to what makes good music, you're naturally going to write music that tests your theory, hence the association between music theory and compositional practice. They are technically distinct, but most musicians use the term loosely. So that's probably where you're confused.
I would not recommend learning about music theory unless you're interested in actual music. Most of your time learning music theory will be spent analyzing actual music, so if you don't like it you're gonna have a bad time. And personally, the benefit of music theory for me is applying its lessons to music that I write. So if you don't even like music, I'm not sure what the appeal would be.
And it worked! I feel my knowledge of things has deepened, and my interests have been rekindled. It's a lot of fun and very relaxing to do.
Essential to all this is a personal wiki that I keep. I'm using Zim (https://zim-wiki.org) which most of you are probably familiar with. I don't often publish anything there - it's just local files, for now.
Never heard of "Digital Gardens" but based on the reddit group they mentioned in the article, it looks like there is an emerging community of people doing this.