Silvina Valz is a good leader and a great instructor. I've been to workshops with her and her dance partner Oliver Kolker. She has led me through moves so I would know better how to lead them (yes, I'm a guy that has learned how to follow in tango a little bit). She teaches some slight nuances of the lead that make a big difference in comfort for the woman.
Some of the comments on the YT clip mention how hard it is to lead in high heels. In her women's technique workshops I've overheard her stressing groundedness for the ladies - is that groundedness what allows her to lead despite the heels?
Since "groundedness" is such vague term - what I mean is that I was taught to be grounded when dancing milonga by keeping the knees slightly flexed, with the hips, shoulders & head over the balls of the feet, my center of gravity low, and the heels slightly raised.
BTW - to see Silvina following while dancing milonga compare her YT clips dancing with Oliver Kolker and with El Flaco Dani.