But nobody's going to fucking use a raillgun, because anybody who can colonize space can also build much more efficient mass drivers. A coil-gun is built using the same kind of technology as a ship's engines, a bunch of fancy magnets that push things in one direction. The only difference is it pushes solid projectiles in a straight line.
Raillguns are weapons that planetary civilizations consider putting on their wet-naval vessels before they decided they don't provide much of an advantage over missiles or conventional guns. Coil-guns on the other hand are the space equivalent of a battleship's cannons.>>55159732
Not really, if you are building interplanetary spacecraft that don't suck balls, you'll need those things for the engines.
The infowar part is a good point though. In the "No stealth in space" arguments, people forget that there is more to stealth than just hiding. It's true you can find out a lot about a ship by observing a drive plume, but if you load a bunch of missiles with different warheads, and make sure they all have the same mass, The enemy will have a hard time telling them apart from each other, esp if you program them to fly in sub-optimal patterns for the purposes of deception. And once the missiles are in the terminal phase, they can deploy decoys along with their warheads, and once they've gone ballistic, you might not even be able to tell a warhead from a balloon. And this is before you get into active jamming, or throwing up reflective Whipple shields so the enemy can't see what temperature your radiators are, which direction you are pointing, or which bay doors are open.
The enemy will always know where you are, and have a good idea what you are, but he won't be able to know what cards you have in your hand and what you've placed on the table. There is still plenty of room for poker in space combat, even without stealth.