Snipers are responsible for the long-range physical damage output of the team.
Their deployment cost is not especially high, making them a good choice for lightly armored targets in the midgame.
However, Sniper Operators have poor survivability and do not hold up under sustained enemy attack.
Put them behind melee fighters to keep them safe.
Note that Sniper Operators are not effective against armored enemies, and will need the support of Caster Operators to deal with hardened targets.