[rahbert]

Can’t the laser be seen and thus give away the troop’s
positions?

[Spktyr]

Infrared laser.

[Reeses]

Can’t the laser be seen and thus give away the troop’s positions?

Yes, it can give away the position of the laser but the laser doesn't need to be at the same position as the troops or robot holding the gun. There can be decoy lasers to flush out or confuse a well-equipped enemy. A sniper bullet is probably not enough in this case.