Seriously, what is Xfce, or even LXDE good for other than low powered devices, like netbooks?
Um. It's a desktop environment. You might as well ask what GNOME is good for.
Um, made specifically for low powered computers.
Modern Gnome seems to be catering towards the up coming tablet craze, while Unity seems to be trying to get its foot in every possible door.
Then we have Cinnamon which is made for the die hard Gnome users with a minty taste of the past.
I have used both Xfce and LXDE, and while they are both fine for what they were made for, they are quickly loosing their customer base.