Because Kotono can act and sound naturally young. Sheh sounds force. I know she gets praised for making Usagi sound young as opposed to Hawkes and Ballatyne making her sound too old for 14. But Sheh doesn’t sound natural to me she sounds like an adult woman doing a forced young teenage anime girl voice. Kotono and Tracey Moore actually sound naturally youthful despite being older. Hawkes didn’t seem to be bothered, raising her pitch a bit but sounding closer to an upperclassman in high school than a second year middle school student. And Ballatyne uhh was more suited playing older sophisticated versions of the character than whatever it is she was doing.