she is not useless, just very annoying and poorly written... people only say that because many times, she is scared, compared to her teammates/sensei and it is not fair for her. am not defending her, am just saying that calling her useless is a bit on the false side. she has trained a lot with the 2 years but the spotlight does lean towards naruto, sasuke and kakashi more than her (which is fair since they have more depth to their characters than sakura)