Put simply: the breakthrough here massively cuts the physical qubits needed to do error-correcting (in the pursuit of logical qubits). What they demonstrated in this regard was vastly more efficient than the current state of the art (as well as what IBM is hoping to achieve in its next generation chip). It seems to have pulled game-changing quantum computing years closer to reality.
The paper: https://www.nature.com/articles/s41586-023-06927-3