Here's what happens when Warne is the frontline bowler. According to
Aussies (including Warne himself) he should have gotten 14 wickets
since there is no competition for wickets
http://www.cricinfo.com/db/ARCHIVE/1997-98/AUS_IN_IND/AUS_IND_T2_18-2...
And here's what happens when Warne is not the frontline bowler.
According to Aussies, Warne faces immense competition from fellow
bowlers to take wickets and will take fewer wickets.
http://www.cricinfo.com/db/ARCHIVE/1999-2000/IND_IN_AUS/SCORECARDS/IN...
Extreme cases? No. Happens most of the time in Test cricket (Just for
giggles sake, compare Srinath's figures in both tests. Srinath should
get fewer wickets at Calcutta because it is a spinners paradise and
India had three frontline spinners to eat away Srinath's share of
wickets)
Bottomline, you get to take easy wickets and score easy runs when your
team is doing well.