One thing to consider is that in piano performance and all other performances is that there is the concept of "showmanship": movements are slightly exagerated or even overly exagerated (Lang Lang). Not all pianists do this and some teachers would forbid any unnecessary movement because it leads to poor technique - it can hinder technical development.
About the wrist: stop looking at her wrists!
About using the wrist: it depends on what the wrist must do to guide the fingers and at the proper strength to play the piano. But...
About technique: "good" technique occurs when you have control over all aspects of the body (i.e. core, legs, torso, shoulders, elbows, wrists, fingers, neck). Picking out one of these, in this case the wrists, has little benefit for a general discussion about technique because in actual use any discussion about it is not beneficial unless this topic becomes much more specific.
What does Elena say about her wrists? Ask her how much it contributes to her playing because only she can answer that (and even then, she may not even be able to explain and if she does, it may not be reliable).