Didn't mention it earlier, but I believe it was the standard option offered and I could switch to wood framing instead. I didn't look into it at the time. I do recall they said I couldn't have roof tiles if I chose a steel frame, but I'm actually looking forward to having a colorbond roof anyway.
Certainly no termite issues with steel, stronger than wood, resistant to fire; supposedly lower insurance premiums because of the termite/fire properties. I'm not a builder, but perhaps someone with a little more knowledge than I could dig up on Google could share beyond that. Naturally their press material will give them a positive spin, but I noticed one thing they mentioned is that the "strength-to-weight ratio allows for wider spans". I'm not sure I have any of them, but caught my eye.
truecore.com.au