>>12535022A woman with soft soles is a sign of nobility, muck like pale skin (having soft soles means she doesn't have to toil, and having pale skin means she doesn't have to work in the sun for hours on end).
The soles of the feet are also a part of the body you rarely see, first of all because people usually wear shoes (except possibly when indoors in a private home, but being in a private home with a woman already signals a certain level of intimacy) and secondly because humans usually stand upright or sit on chairs while interacting socially in non-intimate situations, and in both cases the feet are usually planted firmly on the ground. In other words, looking at a woman's soles is about as intimate as looking at her nipples and her asshole.