She is indeed very good at what she does. And I think the 'flies in the teeth' grin of someone aerobatting is an inaccurate portrayal. Aeros, especially at that level, requires total concentration. I certainly never grinned while aerobatting as I was concentrating too much. Afterwards, yes, but not during.
A lot of the concentration is of "don't F U the manouvre" type. Aeros is about trying to get it perfect; and of course one never does.