The GSX Manual, at Page 40, the chapter named Note for scenery developers explains this quite clearly and basically means:
- Scenery developers supplying a GSX profile, should place the .INI file in the scenery own \Scenery folder.
- Users customizing a scenery will see their changes appearing in an .INI file under %APPDATA%
The reason for this dual approach is that, if you want to customize a 3rd party scenery that already came with a GSX .INI file ( in the \Scenery ) folder, you can play with it, make mistakes, and if you remove your .INI in %APPDATA%, GSX will fall back to the one in the \Scenery, so you won't have to start "from scratch", but you'll start from what is assumed to be an already reasonable customization.
If, instead, we used a single .INI file, if you edited it and made any kind of mistake, you would have to either start from scratch, or reinstall the scenery it came with.