The point is that his bowling is only required when we are getting towelled or need a change which he was successful at, plus can bowl spin or mdeium pace dependent on the state of the pitch.
IMO moving an allrounder into the team as a permanent fixture is about planning for the retirements of warne & McGrath. In that Warne and McGrath are so good that they can carry a 4 man attack but when they retire and we have Johnson and Hauritz
lol: like that would happen) we will need a 5th option bowler.
Symonds batting is not up scratch and we are unlikely to see a test ton in the next 2, but the only other available options are untried and we are better easing them in the team against different opposition.