>>42444041
My interpretation of Octavia is that the reason she is grey-colored is because she is supposed to represent the concept of elegance through simplicity and understated-ness. Grey is the least ostentatious color of them all, it does not call for your attention, it just quietly is. In order for something to be refined, by definition, it must be no more complex than is necessary. Octavia is streamlined, she is focused, she is not grey (the most boring and drab color) because she is unremarkable. No. Rather the color grey represents her because she is controlled, calculated, composed, and focused diligently on her craft. She takes perfection very seriously. It is not the kind of perfection represented by the color white, which is unstained and sanitized. The perfection of grey is something which considers all things, even unsavory ones, and takes it all into consideration to form a complete whole.
Holy shit I'm autistic
Okay idk where I was going with that, but MY POINT IS I think that Earth Ponies take pride in accomplishing things through non-magical means. Magic makes things easy, which means it tends to encourage lazy thinking and Earth Ponies don't like the idea of using magic as a crutch to cheat your way out of hard-earned solutions to problems. Octavia understands this. She wouldn't want to be a Unicorn, which appear elegant but in reality are usually lacking in substance of character (they are superficial) or substance of craft. She understands that if you chop a tree down in 5 seconds with a magic spell, it is not impressive or praise-worthy, but if you chop down a tree in an hour with a saw, that is impressive and praise-worthy, because it was a hard-won task that made you stronger as a person by doing it. She knows that working physically with your hooves is very important for mastery with things and I do not think she would want to be a Unicorn because if she could use magic to play her instrument, it would no longer be impressive. And she would not come to come to understand the complexity of her art fully because magic is taking the easy way out.