Indeed, the 26-year-old's album covers - the latest one, out next month, is called My First Decade - frequently focus as much on her million-watt smile as the million-dollar violin she plays (the Gariel, a 1717 Stradivarius loaned to her).
Sitting in her west London flat, Benedetti shrugs: "The whole discussion about separating different elements of performance from the visual appearance of the likes of Alison Balsom or myself is ignorant," she says. "When people go to see a live performance, they are taking in, on all sorts of subconscious levels, everything about that person - but it's more than just what dress they are wearing, whether they are fat or thin, what colour their hair is, or how exactly they sound. It's the entire feeling that you're getting from the stage and it can be a combination of the most superficial to the most spiritual."
Yes, but isn't it frustrating to feel you're judged because of your looks? "No, it's beneath getting frustrated over. These discussions aren't exclusive to classical music. I think it's yet another sexism debate, a sex-sells debate - nothing new."
Benedetti's father, Giovanni, moved from a small village in Tuscany to West Kilbride in Scotland at the age of 10, speaking no English. But he had a drive to succeed: after leaving school he invested in a dry-cleaning shop that became a chain, invented a cling film dispenser and then a first-aid kit, building a business empire along the way. He married another Italian migrant, Francesca, and they had two daughters, Stephanie and Nicola.
Francesca was loving but strict; there were fewer toys than their less well-off friends. Even now, Benedetti seems to retain some of this careful attitude; although her flat is in an expensive part of London, it is relatively small for a girl who signed a £1 million ($2 million) contract at the age of 16.
There's space for an upright, but not grand, piano in her open-plan living room; her brightly printed trousers come from Top Shop, and she says her mobile phone is her biggest extravagance.
Benedetti started playing the violin at the age of 4 and her talent was quickly apparent. She earned a place at the Yehudi Menuhin School in Surrey, going on to win the Brilliant Prodigy Competition organised by Carlton Television, and then Young Musician of the Year at 16.
Francesca used to make the sisters practise for three hours a day in the holidays before being allowed out to play. But Benedetti is grateful. "The benefits of persevering are so much more than what everyone usually obsesses over, which is having fun. Fun is great, but fun is a momentary thing - it's not something you can fill your life with, or that will sustain you through hardships. I wish this was vocalised in education.
"I think there's been a huge increase in a kind of false confidence, so young people will say 'I'm proud of myself' but if you criticise them, they get offended, defensive and upset," she says.
"My entire memory of being in school was being nervous all the time. It was just that I cared a lot and I was scared of doing something wrong. I think that did me the world of good, because you have to learn that fear and respect some time, whether at 11 or at 18. I would put my money on it being much harder to learn at 18."
She is highly critical of the loss of control that has become prevalent in some classrooms, engendered by lack of respect. And she feels that we need to return to values of community. "Politics do interest me," she says. "I have to be careful, people don't like it when musicians get all political and preachy. My dad is always warning me to shut my mouth, but I can't help it. I would be some sort of activist if I wasn't a musician. I have to curb my enthusiasm for that all the time."
But then she sees musicians as political by their nature. "Art has so many different functions - to reflect the times, heal the times and lead the way. Sibelius is one of the greatest examples of that, when he was at the forefront of Finland's movement towards independence. There is no significant point in history where music has not been predicting what is going to happen or perfectly capturing the whole mood."