Lubricant compositions range from wax emulsions to soap compounds to emulsions of polymers in water. Some lubricants do better with certain combinations of cable jacket and conduit materials. Friction numbers vary A cable and lubricant combination with a lower coefficient of friction will pull with less tension. That makes sense. But comparing lubricants can be tricky, because there are so many variables.
Lower friction reduces pulling tension, which decreases sidewall pressure in the bends.
That protects the cable and increases overall reliability. Sidewall pressure can also stress the lubricant. That makes the boundary, or thin-film, performance of the lubricant important. If it isn't, it could affect cable life, especially at higher voltages. UL-listed lubricants have been investigated for compatibility with common cable jacket materials.