Air NZ 747 in Brisbane

In the newspaper there was an article about a storm that hit Brisbane earlier in the week. There was a picture from the terminal with an Air New Zealand 747-400 with lightning in the background. Why was there a 747 in use on that route? I read another forum and the people couldn’t agree, someone suggested that the aircraft regularly swtich and they use any Air NZ wide body - although this is not the case.

No first hand knowledge here but I did read on the internet that the Brisbane-Auckland route is one of the busiest across the Tasman.