Servo Drive - step multiplier

Hello all,
Can someone please tell me the principle behind the use of a step
multiplier in a step and direction input servo drive such as the
Geckodrive 340 or the Rutex RT990a. I can understand the rationale in
the case of a stepper drive and micro-stepping to smooth the motion.
However this would not appear to be a requirement in the case of
servos. Hope someone can shed some light on this issue.
Regards to all.
John C