Dancing alone as a way of practise works wonders for creative musicality, and footwork. And it has been an equal part of our evolution, alongside social dancing.
It feels essential for building individual style. Yet it goes further than that. It helps us to know how we like to move. And to feel comfortable with any song, any partner.
Interestingly enough we have found it to be the same with many others; I have heard of similar experiences with social dancers of Salsa and Bachata. It really seems universal - like knowing yourself by yourself is essential for staying true while connecting with others.