You're kind of implying that failing memory is unusual/exceptional and that it needs particular attention.
Here's the cold hard truth of memory: your memory isn't as good as you think it is. No one's memory is as good as they think it is. And nothing you remember comes back out of your memory quite the way it went in.
Writing good, complete notes that could be read by someone else (complete sentences) helps you design the prompts for your future recall of something complicated. Because one day you'll be that someone else.
When I write code, I try to write code and comments that a version of me that is ten years older and persistently two hours short of sleep will be able to cope with at 10pm. My tireder, older self. Because one day he'll have to read it, understand it, and change it.
I try to write notes the same way!
That might be your personal experience/bias speaking.
For many creative endeavours there's not a "single project" where you do research, finish, wrap up and that's it. You need to track lots of pieces of information across many projects, domains, and across time.
The usual way to track knowledge and tasks is within a project. You come to a road block, do research, overcome, and continue.
But many of those note taking posts talk about personal "wiki" projects and tracking _everything_. I suspect that with ADHD its hard to filter out the important things from background. And based on my observation wth these apps people start organizing and remembering this "background". When background noise is reduced the need for complex apps is no longer there - there are a lot fewer things left that are worth remembering. (exceptions apply, of course)