Ultimately, it depends on the type of user but the "barrier" may be that it's plain text. So Org Mode's data format as a desirable selling point is also its ceiling of functionality.
Yes, I store 90% of my notes in plain text. But I also store some programming notes in MS Excel because I need a datagrid as UI with dynamic calculations. I store some project notes in MS Word because I need to embed graphics along with text. I suppose I could use Org Mode as a "single source of truth" by linking to .xlsx and .docx files but I reorganize my folder structures too often to make such file links stable.
I made a previous comment why Emacs Org Mode along with everything else I tried in the last few decades to organize life is a very hard problem of "boiling the ocean": https://news.ycombinator.com/item?id=23112843