When i think of "desktop integration", i think about drag and drop not working between `ark` (a QT program) and `thunar` (a GTK program), and i think of folk writing blog posts about window theming. (there's also notifications, icons, etc, blablabla, that keeps getting worse (freedesktop is, that is))

To be honest, i don't care much about how programs look. But i do know many people do care.