Just like Pudding, I loved her in just the one chapter they used to formally introduce her.
I mean look at this adorable shit:
Out of all the characters I've ever wanted to join or suspected would, none come off as so obvious a fit as Carrot does. Puts Dressrosa arc in particular to shame, I remember everyone bickering over mediocre choices like Rebecca, Barto, Cavendish, Bellamy (Dear lord no), even Law, etc. Carrot crushes them all. Hell, she even would give Jinbe a run for his money concerning characters that are likely to join the crew, if it weren't already declared multiple times that Jinbe is joining.
Also she has to join, so that she can continue her adventures with Bropper. Additionally, I always felt that this crew could use a 3rd female member, so who better than a character that would basically be the little sister of the group? Which contrasts well with Nami being the middle child, and Robin's big sister persona. And as others have said repeatedly, it would be very nice to see a female brawler.