AWS Cat Qubits Make Quantum Error Correction Effective, Affordable

Material science and biochemistry are usually cited to be the primary beneficiaries.

A fruitful avenue may be in quantum simulation, i.e. simulating a quantum system and computing its properties. This is why the other commentor mentioned biochemistry and material science, since these are two domains where quantum effects are important to understanding.

To give two concrete examples:

In biochemistry, we could hope to understand how bacteria are able to do nitrogen fixation, possibly leading to a more energy efficient and less GHG-emitting alternative to the Haber process.

In material science, we could hope to better understand the mechanism for current high-temperature superconductivity, possibly leading to the development of superconductive materials at even higher temperatures, lower pressures, and with more convenient other properties (such as toughness, ductility).

Yes, they use superposition of the most "classical" quantum states (coherent states). These are called (Schrödinger) cat states, since his thought experiment was about a quantum superposition of a very classical object (a cat): https://en.wikipedia.org/wiki/Cat_state