Artillery with spotters accomplished the same task.
Sure, you can use your spotters to scout ahead, but why put them in danger of an ambush and have them get killed by a sniper or hidden machinegun, when you can survey that area from a safe distance, and take out the sniper/machine gun if you see one?
This is not meant to replace artillery battalions and scouts, but to complement them.
Kamikaze drones have a role for the smaller units, but at the battalion level, it's better to use a surveillance drone to coordinate fires from mortars, MLRS and artillery. The rounds fired from these systems typically have longer range than a drone, a higher rate of fire, and larger warheads.
You can put the spotter and the artillery in your backpack? The task is only one part of the equation.