[causalmodels]

Fast.ai works pretty well when you're working on standard tasks but starts to fall apart when you want to do something more exotic.

[deeeeplearning]

I doubt there's much in CV for instance that couldn't be achieved easily with fast.ai. You don't need to be doing exotic things to build a product.

[causalmodels]

Never said you need an exotic model to build a product nor that you couldn't do exotic things in fast.ai. Fast.ai is just a leaky abstraction.