Tactical pants, or field pants, are lower garments made especially to respond to the requirements of the mission. They offer increased protection from elements while allowing maximum for mobility.
Yes. Due to materials tactical pants may cost more, but the protection from heat, cold, and moisture will reduce down time, injury and infection rates, as well as increase combat readiness.
They are made to retain flexibility and mobility even when equipped with additional gear or has other items like belts and armor attached to them. They are used for a plethora of demanding activities.