Spotters at MILSIM games are a great help, where you have been given an objective or a target. However, in normal skirmishes spotters are unnecessary in my opinion. I like to have a friend with an AEG staying with me though to provide support when encountering multiple enemies who are shooting at me though, but he doesn't act as a spotter.
People communicating well over the radio is good enough for me!
People communicating well over the radio is good enough for me!