Cost and off-road prowess.
To make the SE more ADV-like will be easier and cheaper in the end. I also didn't want to constantly worry about damaging expensive plastic bits found on the ADV when off-road (let's face it, I crash..alot (if you're not crashing, you're not trying hard enough)).
I've upgraded my SE for the same reasons. Since the picture was taken I've added a Renazco seat. The bike is all-day comfortable now and still retains great off-road capability.