Good day @phw,
The wrapper is just some C++ code that executes the python app in order to give the Python app better integration in the Haiku Desktop:
- like its own icon,
- file type association
- file type icon
- double click launch from the tracker
- double click on file launches the app and opens file
- appearance in the app list in the deskbar
- packaging as hpkg, and hopefully through haikuports
Those sort of things. Actually, my “other” interest is learn to hopefully code native python Haiku soft… ehem… … … … someday 
Regards,
RR