@alltagsverstand:
This is not the platform to discuss the pros and cons of other apps, so I don’t think we should go into too much detail.
It’s been 3-4 years since I stopped using it so cannot remember all the details. What are called “keywords” I did not find intuitive to use, nor the linking. The imposed sequential numbering did seem to add value, and when you delete a note and create a new one you can reuse that deleted number. I did not like the vendor lock-in for file format, as you acknowledged. There was more. I cannot remember the exact length of time I used it, maybe not long enough because I did not experience the explosion in productivity of reading and writing.
So, maybe I am not being fair, but the apps I found the apps I used afterwards to be a lot more intuitive.