Because I'm not exporting but saving, and it doesn't work the same way as Ctrl+S should. If I have opened a file and changed it, I expect Ctrl+S(/E) to override it. What I do not want it to select a file or answer dialogs, asking me if I really want that. And when I close the app I don't want to confirm that I really don't care about xcf and yes, I want my changes "lost". And I especially don't want to lose my changes because I thought that I have pressed (Shift?)+Ctrl+E and that this warning can be disregarded.
I might be wrong in some details because it's been a long time since I last used Gimp without this plugin, but the whole process is so brain-dead that it is incomprehensible how anyone could defend it. I am guessing that if one of the core developers had to manually edit 100 PNGs they would revert their position in a blink of an eye. /rant
I mean if you could just leave out the front side door you could use those resources to improve enter-abilty through the back hatch.
This could also improve the loading and unloading of goods through the back hatch for more professional uses.