Hello and welcome to COL
In the UK crossing show and working type Cockers is frowned upon by reputable breeders in the showing world and working world. I used to compete in agility with my show type and used to see quite a few show types and workers competing but as far as I know nobody in the agility world was crossing the two types, although some were looking specifically for small sized workers to be eligible for small height classes. There's no doubt that workers tend to be much speedier in the agility ring than show types, but both types seem to take to agility readily in terms of attitude and trainability.
It sounds like you may not have seen many workers as there are so few in Australia, but after being bred for their working ability for many generations they tend to have a high work drive and lots of speed, but a lot of variety in size, build and confirmation, from pocket rockets to giants, fine boned to lots of bone, good confirmation and soundness to poor confirmation. No disrespect to those with workers, but they are much more varied as a type than show types are.
Most, perhaps all, of the show/worker crosses here in the UK are the result of backyard breeders randomly crossing the two types and selling them as pets. Sadly there are many people who don't want to pay much for a pup and haven't done any research about the breed and who are happy to buy from the litter bred just down the road or advertised online cheaply, no questions asked. There are also breeders happy to pull the wool over buyer's eyes and tell them their puppy is a show type when it's a show/ worker cross.
Because of the differences between the 2 types you could end up with a litter of pups that are all different to each other in size, confirmation, coat and aptitude for working. You could have puppies with a profuse show coat and a high work drive, puppies with very little coat and a laid back attitude or anything in between. You might get a perfect agility dog but equally might not.
If you're planning on getting a worker bitch and competing with her, that will give you time to get used to the differences between the two types and seeing for yourself that crossing the two could be a game of chance.