I notice that Ms. Vidovic often involves the elbow in her thumb stroke, which entails displacing the right hand, sometimes by a few inches or more. To be more precise, I see a combination of elbow and thumb movements with a subtle wrist assist. I haven't encountered this technique in classical guitar pedagogy--it's more reminiscent of piano--but then I don't have much formal training either way. It may be more typical than I think.
It's apparent throughout this video, especially in the crescendo that begins around 0:50 -- https://youtu.be/dmc6KV0_UVM
When I attempt it myself, I enjoy it, especially the sensation of my arm being free and active (which I admit I should be feeling all the time, which, if nothing else, makes this stroke a good exercise for me), and I find that it promotes relaxation in my hand.
Does anyone here use their elbow this way? Or teach this way? Or is this actually standard practice and what I perceive as atypical merely a matter of degree? I welcome any thoughts.