Because of course the F-111 was such an outstanding success for the RAAF, right from the very beginning, and even more so for the Aussie taxpayer.
EF with conformals vs JSF in the RAAF context? No contest.
NB: When Australia got its Spits the US alternative was the P-40. When Australia got Meteors the US alternative was the P-80. When the RAAF procured Sabres, the UK alternative was the Hunter 6/9.
But you've already made your mind up, I guess.