Yeah you're right, but imagine if Carrot end up joining she would be useless like them on the Sunny, jumping around being cheerful, copying other Strawhats reaction cause she has no of her own, some garchuu crap, oh this is a wonderland crap. She would still be in the background saying wow Chobro you're awesome, only reactionary stuff, or wow Nami your dress is so beautiful..
When has Carrot ever been cool like this in any speudo fight she had?
That and in her introduction, that's it, else she's shown with Nami and Chopper afraid or some boring comedic response.
Its a tough call, between Momo and Tama being useless and Carrot being a moving cardboard..