My first thought was that a weapon like that requires line of sight, and for that LOS to hold stable throughout the projectiles travel, which would only work if you're targeting fixed sites like buildings or bunkers. Since the projectile doesn't carry an explosive warhead, the hit would have to be dead-on to be effective. I did serve in the military but I'm no engineer, but that limitation seems a deal-killer to me. But hey, I've played video games with handheld rail guns, so what the hey! 🤣