There are lots of features I don't use in org. In fact, in the beginning I only used the most basic feature of keeping a foldable hierarchical text file of notes, which is basically the same thing as your Notes files, but with some nice structure editing and folding keybindings built in. But I have been slowly integrating org features into my system when I think they would be useful to me.

First I started scheduling things. With org, you can schedule items and have them show up in your agenda regardless of what org file they are in. Org agenda gives you an outline of your week, and your current day, and it says how many days you have left until certain items are due. This has replaced my calendar, and feels superior to a calendar to me.

Then I started using org-drill, which lets you drill org notes, emulating the spaced-repetition behavior of Anki. You could just use Anki, but it's nice to have all of your personal information management in one place, and have it editable from your text editor.

I've also started using hyperlinks to make links between my org files and also to any other file on my computer, to web URLs, to executing a script, to mailto links... This has been helpful.

I still don't use plenty of features, like the literate programming stuff, tables, tags, capture, etc. But I don't need to. They're there for me if I feel they would be helpful. But they're invisible to me otherwise. Org isn't "insanely complicated" because it's mostly just a text file, and the features are there for you to use if you need them, but there's no cluttered UI that actually adds any complexity.

I suppose this is for the same reason that people structure databases. There are often non-trivial relationships between different types of information that are useful to keep track of. Citations and links are useful features for note taking.

Because "great search" is not even close to good enough and handles only a fraction of the features.

This is like saying that excel is insanely complicated for no reason, when pen and paper exist. If this is all you need, great, but if it is not then the comparison does not even make sense.

Notes and reference material benefits from good search tooling.

But tasks or todo lists benefit from being well-organised.