Talk:Twilight Sparkle (Sci-Twi)/@comment-33007990-20170901210925/@comment-10390252-20170903194436

Mostly it's an aesthetic thing to emphasise the character as a 'nerd' or 'geek'. In-universe, it's worth noting that Princess Twilight uses reading glasses in several episodes. So, I'm guessing that Sci-Twi needs them as well. She's just so absent-minded that she wears them all the time so she doesn't have to search around for them when she needs them.