I'm a bit of a "hand-waver" and I blow sometimes kisses, but I don't at the piano. I sometimes get remarks that I do some grimacing at the piano, but that's not on purpose. I think it (the grimacing) goes with the performance. It is in the end of course something that is not totally 'explainable', but it comes along with the intention to communicate for example 'your vision' of the piece. Even if it's not a vision, but just a certain mood, I'm absolutely part of the 'school' that needs a lot of concentration before the attack. Really, if I'm at home and want to play a piece, a can start the first measure four-five times again, and still be not satisfied with what I'm hearing. I can't play like that (to take a popular example) Moonlight of Pathétique without a like ten-fifteen seconds of focus before hitting the first note. That's my explanation for the facial expression. Now the movement of the hand together with facial expression is maybe well illustrated in this link and the next one (there must exist better and more "explicite" footage, but I think Bozghanov is wonderful example of performing with the involvement of the body)
I'm a big fan of this pianist. He is so unique, so "free", so stubborn in what he's doing, so compromise-less. And I think I can share with him the idea that the whole body is really involved in pianoplaying. There is a lot to be said and unsaid about energy. Where does that energy come from. A deal from gravity, from out of the ground, throught the bench and the belly through our arms. I personally can't separate mind and body, or mind and energy to be more precise. But I really don't know how it exactly works. (There must also be a part of the energy coming out of the universe, no ?) So, I think the body movements is for a tiny bit of course a choice, everybody can play in a certain way just with moving fingers, arms an torso, theoretically. But if you really want to produce music, every fiber is involved, we should not find it weird, for me it's really normal.
To play devils advocate: on the other extreme there are pianists who seem to have a total physical disconnect with the music. Instead of hand waving they approach the piano as if nothing special was going to happen, play as if they were filling out their tax return, and finish as if the only thing on their mind is to get away from the piano and do something else
Absolutely. And I'm quite sure, that those are not the best performances one could hear.
Maybe a little weird comparison ; when I cook for family and friends, the whole kitchen is really a mess (that's what my friend says). I can cope with that. It's just like that, I only hope that the dish is enjoyed. And yes, I try to cook wisely, not to throw too much away, slice fruit and vegetables thinly, keep the bits that are left over for the day after 'tomorrow' etcetera, not to spoil ingredients. But yes, the kitchen can be a mess.
So, the handwaving, for me, goes along. You think as a musician to give the best. And even if it looks sometimes exaggerated, I myself, just try to enjoy what I'm hearing and not what it looks like.
Kind greeting to you all.