I think the CIWS turret or Howard should get a option to use tracer rounds because it looks more realistic like the real CIWS do.
I just think it would be cool to see at night when defending from missiles

This is all conjecture and could totally be wrong, but I am pretty sure the CIWS is a hitscan weapon, meaning if it can, it instantaneously hits the entity it is pointed at.
kinda like GTA bullets traveling instantly any distance. This is my assumption anyway since this is the only weapon I cannot see any projectile with when fired, even when I slow down the game to 1 tick per second. You COULD go the flan's mod route and have hitscan weapons and also have a separate completely cosmetic entity that shoots out too.

Like the thing with TF2 bullet particles.

Le trace bullets