If my memory is right, modelling like that does poorer overall than having your general classifier find the banana.

The mental models we have to describe these things don't match well to how the ML breaks down such classifications. Finding a fruit without having already figured out that it's a banana is pretty hard.

So then you're kinda stuck with "looks like a cylinder" so your second one could distinguish hotdogs from bananas, but that's already what the layers of the neural network are doing