Kill Sat: Oh, yeah. See also Death From Above and Wave Motion Gun, because there’s no artillery like ortillery, and no high ground like orbit. The orbital defense grid (it defends orbit from above, it defends orbit from below, and, of course, it’s in orbit) that any self-respecting planet has is the stereotypical example, but should you need to carry out a ground assault on someone else’s planet, you’ll almost certainly carry a few of these along for orbital fire support. And, yeah, they generally aren’t that much trouble to move around or fire repeatedly, so when one is around, it is generally not a good idea to stick your head out into the open, lest it find “Rods from God” or phased-array lasers raining down upon it. Or, indeed, to approach the planet from space, lest you find them raining up upon it.
“Poor form to snipe your opponent from such a risk-free distance — generally the realm of villains”, indeed. This is war, boy, not lawn darts! They don’t give out points for fairness.