Hi, I hope this is the right place to ask this, if not I can start a new thread.

I have AirNZ Gold Elite (Star Alliance Gold) status and use Airpoints.

I wonder if it's possible to upgrade Singapore airlines flights (premium economy to business) using Airpoints?

Does the Star Alliance Gold status confer any benefits when flying on Singapore airlines flights?

I much prefer Singapore over AirNZ especially business class.

At least one trip to Europe a year, is it worth signing up or switching over to KrisFlyer? I have stuck with airpoints so far, I am much more interested in status points to keep the lounge access which I value very highly.