I am wondering if spotting the enemy will yield any small measure of exp, if you are the first to do so, in say an hour? Mechwarrior Online is finally being the first game to reward this very useful action, its taken many years of calling it for and its great to see.
Scouts help, as you know where your killing
, and what is headed your way, they can swing the match by giving people advanced warning. This in turn leads to the people commanding the larger units hitting or defending the right places. Scouts would include cloaked units but also air units, fast vehicles, anything forward enough to get a trace on the enemy.