I think submissives who have a thing for feet and heels are going to be all over the place on this topic.
I for one love sexy heels, especially shoes showing off pretty feet. They do make the legs look more toned, longer, and attractive. For me high heels are like "mini pedestals" for the goddess/mistress. It seems to me easier for a woman to be dominant wearing heels than if she is barefoot, wearing flip-flops, or some other flats. While she may be in fact very dominant, a woman wearing flip-flops or going barefoot does not at first glance LOOK dominant.
Also as a foot fetishist, I find pretty, well-cared-for feet to be very sexy. Such feet can tell the submissive that the mistress is hygienic, which is important for me because I like orally worshipping pretty feet. (An old saying holds that cleanliness is next to godliness.) I personally detest dirty or stinky feet but I know some folks prefer them that way.
Part of the eroticism of a sexy dominant in sexy heels is the way she can so easily administer pain with so little effort on her human footstool or human carpet. Furthermore, the submissive taking heel pain for his mistress is a form of worship. His pain is his gift to her.