What I see in Charlotte is the word 'harlot', clearly visible and very off-putting. Plus, I agree with you about its clunky harshness and I also rather dislike unisex nns on female people - Sam for Samantha, Toni for Antonia, Jo for Josephine etc etc. And given Charlotte, Charlie is pretty inevitable.
It's got an 18th to 19th century vibe which is fashionable, joining Lydia and Emma, so perhaps some folks see period charm.