While Spike in its latest version has a longer range than similar weapons, I think you're also ignoring some of its disadvantages. You mentioned the higher cost, but the biggest problem is that it still uses a wire, which means that it has to be connected to the launcher, making the launching platform vulnerable (it has to stay in the area). Although still called a "fire and forget" weapon, I personally do not think any wired weapon is fire an forget. A true fire and forget weapon means that you can leave the scene or flee from potential enemies, rather than having to stay at the "crime scene."
Spike really allows the firer and loader to leave the crime scene. The fiber connection to the missile allows the firer to update and guide the missile, e.g from the turret ring to somewhere else like engine, thats all. I'm spike trained btw.