I am an authority in the topic because I am extremely limited in my ability 😄 .
Nevertheless, it follows the logic that you are better equipped to learn musical nuances if you train with an instrument that allows more nuance. Thus, sensitive action trumps less sensitive action, VST or better sound engine trumps pianos with low count of tone layers or bad pedal implementation, and acoustics trumps them all. Does that mean that you will be a better player by learning on an acoustic? No, but it means that you have less excuses not to be good 🙂
I don't want to say bad things about the lady Viktoriya Yermolyeva, but I don't think she is a particular good example of a very expressive piano player (of course she is much better than me, but that is a meritless easy accomplishment). What I find entertaining is the opposite exercise: how expressive can you be when using the bottom of the barrel digital pianos? The casio CDP-s100 is as entry level as it gets. And under the right hands it is capable of this:
so, if you acquire a very good technique (on the s100 or in a Steinway) this is the limitation that you can expect, and it only gets better from here: it is a significant limitation (he would sound so much better and more expressive on a grand), but probably much smaller than expected.