I know as recently as last year the Australian Reptile Park was appealing to members of the public to capture rather than kill funnelwebs, especially on Sydney's North Shore where they are common, because the Reptile Park staff milk the spiders for the venom so the CSIRO can make antivenene, and they were running short. I can't do links, but since it was in newspapers at the time it shouldn't be hard to find. And you might find interesting any of the books by one of my old CSIRO bosses, Selwyn Everist, who was an expert on Australian poisons. Lovely man.
And I can't speak for anyone else, but as to why we're here, my father settled in Australia after WW2. He had suffered horrors during the war, had been in a hospital here after being a prisoner of war reclaimed from the Japanese, and decided it was the safest place left on the planet to raise children. Which socioeconomically, at the time, it certainly was, though a lot of the freedoms have disappeared since, as global culture becomes more homogenised. He figured the wildlife was less of a hazard than wars and politics elsewhere. My grandmother came out here to care for him, and other family members came too. A couple of branches of the family had been here since the early 1800s anyway, and some of us intermarried with some of them, and here we are. For myself, I'm here because the land answers me.
And as for grade D cats, how about 'disoriented and distractable'?