Alright, I'm gonna set the record straight before this argument escalates. This is not star trek. this is not Mass effect. Tech isn't pretty, that's the important part. And yes, consider this; On a colony world, how would you prefer to arm your poorly funded group of explorers, with Reliable, cheap, and easy to produce AK-47s, or extremely complex Coilguns that constantly need repairs from the stress put on them, not to mention a power source, a means to recharge that power source, and the ammunition itself. and conventional guns can operate in a vacuum. The shells are sealed, all the air to ignite them is inside the cartridge, and the round are propelled by the gas forcing it out of the barrel. In fact, with no gravity or air to cause friction, the rounds would have a longer range and be more accurate.
Point is, man-portable Gauss/rail technology was declared pointless for Railguns that small had a very small advantage over Fire-arms, one that did not justify the cost, upkeep, and complexity of the weaponry. however, railguns of a sufficient size are MUCH more powerful than cannon of the same size, and are a necessity. That's why the answer is no.
As for ship armaments, that depends on what kinda ship you guys want.
Fast and nimble?
Durable?
Powerful weapons?
Just pick one advantage and one weakness of your guys' ship, and I'll see what things I can whip up.