[Qt-creator] What are advantages to have Core plugin over MainWindow?!?

[Szyk Cech]

Hi
I just read some docs "Extending Qt Creator Manual" and study 
qt-creator/src/app/main.cpp file. And I have question (maybe not very 
wise but important to me):

What are advantages to have Core plugin over MainWindow?!?

I mean MainWindow class which handle whole app skeleton (located in main 
app exe module).

One reason for core plugin, from my point of view is that core plugin is 
shared object which can easily share its methods to other plugins - I 
think it is possible for exe (app exe module), but counter intuitive and 
cumbersome, and platform specific.

There are some more reasons for create Core plugin?

thanks in advance and best regards
Szyk Cech