Apart from the monetary cost, what does it matter if we keep troops there?

They aren't conscripts and it's highly unlikely that their motivation to be there and fight is driven by any higher ideal like bringing democracy to Afghanistan or protecting Australia.

They are there to do what they signed up to and were trained for.... go to exotic places, get a buzz by being there.... and to fight.

Saying something like the war is pointless or unwinnable is a crap excuse to them.