It's a deep learning based emulator of a full-complexity NWP system, but it is far from a production-ready or operational technique.

It’s an example of a surrogate model. It’s an ML model trained on the output of large numerical simulations like the OP, rather doing the simulation itself.

Surrogate models are nice because they can emulate the output of the full fidelity calculation in a fraction of the runtime, but they typically are trained within a range of validity outside of which they cannot reliably extrapolate.