No worries mate.
I was wondering the same thing pre-Assessment Day and in the end I only had Pilot as a preference. If, like you say, the likelihood of you pursuing another career in Defence is slim, then I wouldn't bother putting in any other preferences.
But with that said, do look into other Defence careers in case Pilot doesn't work out, if you haven't already. I'm gunna take an educated guess here and assume you want to fly fast jets in the RAAF, so if you don't get Pilot, you could go for ACO and eventually be aircrew on the Super Hornet, which would definitely be still worthwhile. Or you could go for Pilot in the Navy or Army. There's plenty of opportunities available, give them a think.