Microsoft Word 2007 introduced what Microsoft called "the Common User Interface", which is characterised by a large ''ribbon'' toolbar in place of the earlier collection of smaller toolbars with pull-down menu lists.
The WordStar Command Emulator was written to modify the older toolbar style used in Microsoft Word 97-XP. The toolbar and menu commands are not ''hard-coded'' meaning that you can change them if they conflict with something else you use, or just because you prefer alternative menu commands.
The alternative would be to assign the commands withn the program code, which would mean that you either wouldn't have the option to change them afterwards, or that additional coding would be needed to provide a way for you to change them and to save these changes. This is the system that would be needed to implement a proper Ribbon style set of menus, and as a consequence, versions of Microsoft Word that use the Ribbon interface put all of the WordStar menu additions into an Add-Ins tab in a seemingly random order.
As WordStar is mainly about using the keyboard to accomplish a writing task, the extra work and restrictions that would be caused by programatically imposing a menu or Ribbon system was not considered to be of value.