My first reaction was also that electrostatic motors would not be useful. Seems to be the "common wisdom". Probably started by this guy (corona motor inventor):
"Poggendorff's negative attitude toward the usefulness of his design may well have retarded its subsequent development."
By the 1870s, magnetic motors were (understandably) taking the lead:
(Wikipedia) "The modern DC motor was invented by accident in 1873, when Zénobe Gramme connected the dynamo he had invented to a second similar unit, driving it as a motor. The Gramme machine was the first electric motor that was successful in the industry."
Engineering-wise, high-power/high-voltage electrostatic motors are unexplored territory. Maybe modern materials can make them useful for niche HV applications.