I don't think it matters. The forecast isn't great.
I also think that MC's captaincy in general is more adventurous than Cooks.
I can totally understand however him wanting a substantial lead. 350ish, which is hard to get in a day. Australia need a win though.. the draw is no good. Cook in similar circumstances would probably bat all the way though till tea on day 5.. just to be sure!
If the light/weather/umpires hadn't decided to end play early there may have been a chance of a result (but it would have required a brave declaration) I think. Now, I cant see it being much other than a draw which is a disappointing end to what has been an interesting match.

