Sydney used to have an Express Path like most airports around the world do. But during recent post-Covid renovations, they for whatever reason abolished this in favour of this rather strange queue for “Business and First class passengers. No idea why, my best guess would be to not have all the status passengers from Economy use it.

So now you have the BA quirk of not calling their Business class a Business class and you have the Sydney quirk of utilising this strange priority system and voila. As an aside- this queue hardly ever saves much time in Sydney, depending on time of day it can even be quicker to just use the standard queue.