The US and Australia have had a 'special relationship' going back to WW2. Even more special that the one with England in this case. The US has a solid friend with a fantastic back yard where they can do all sorts of stuff nobody can see or bother them through public information channels about. They also have this in a pretty damned convenient location in regard to our current global adversaries. Australia has a friend with deep pockets that wants to come over and play and bring the very, very best toys. Sounds like a win-win scenario to me.
North Korea has had a number of missiles just blow up on the pad. Could be coincidence. Maybe not. Ask the Iranians if they think the problems with their nuclear facilities are coincidence.