The Problem with Orbital Bombardment
The problem with orbital bombardment is that it can be extremely effective. This creates an issue in fictional settings where worldbuilders do not want every intergalactic conflict to end with the utter destruction of every inhabitable planet. Worldbuilders solve this problem in a few different ways. Future technology can help – in this case the addition of planetary shields, defensive orbital rings, or similar elements to limit the effectiveness of bombing from orbit. It may also be taboo to target a planet in this manner, and if warfare conventions exist, it may simply be a war crime.