Why is Jadeja in the Indian team?

If Dhoni doesn't believe that Jadeja can last the final few overs of close run-chase, and that too in the company of Sachin Tendulkar who is already on 150+, and sends Harbhajan in ahead of him, then why on earth is Ravindra Jadeja in the team? Surely Rohit Sharma, Yusuf Pathan or Virat Kohli could do much better. Or is it necessary to have a so called all-rounder in the team just to maintain "balance"? In that case compare Jadeja's performance with his Aussie counterpart - Watson scored 93 and took 3 wickets. Out of the two teams out there, in the morning one of them was struggling to find eleven fit cricketers who are good enough to play international cricket. Unfortunately, it seems like that was the Indian team and not the Aussies.