“SoundStream at 3 kbps outperforms Opus at 12 kbps and approaches the quality of EVS at 9.6 kbps, while using 3.2x–4x fewer bits.”
Opus and EVS fall apart below about 3 kbps. A neural codec at that rate now beats Opus running at four times the bits. That matters most on bad mobile links, where calls drop today. Decades of hand-tuned signal processing just lost to a model trained on audio.