hopefully it will at some time be possible to 'link' directly to wanted apps from the UI, it may bring up the desktop, but it would seem (as with firefox allready) that it really is not necesarry to pull up the full KDE desktop (is that 'X'?) to use a single application (I don't know)?
X is the basic display system that runs on top of the OS and its video drivers. The KDE desktop is an app (collection of apps) built on top of X (with some middle layers, like a Window Manager). Firefox and other apps built for the Desktop can run on just the Window Manager, without the Desktop, if those apps don't require any of the Desktop apps running to run themselves. Sometimes these apps can use just the Desktop libraries installed on the machine, and call them directly, without actually calling the Desktop apps themselves (that is how apps from "the other Desktop", like GNOME, can run in one's primary Desktop, though their visual styles will usually be inconsistent). And sometimes these apps can run directly on X without even the Window Manager. X offers more than just app access to the display systems: it also offers complete "network transparency", which means any machine with X can be the display for any other networked machine with X just as completely as the display can run on the same machine as what's displayed (provided the network and both machines are fast enough to keep up). Though I'm not sure whether the Orbiter works that way, it's one way that Unix/Linux machines have offered "follow me" and other similar remote control/processing for decades, and offload display processing for a faster "headless" machine and a more lightweight display machine.
So there's several ways to give LMCE direct access to other apps installed on any of its machines. But I'd prefer to see "Generic App" available as a Media Type, so it's all consistent and simple.