Answer first
Full-duplex is a product-shaping capability, not just a model benchmark label.
The term becomes commercially useful when it helps you choose the right interface, routing pattern, and handoff behavior.
A full-duplex voice system can keep track of an ongoing conversation in a way that feels closer to a phone call. That affects how interruptions work, how quickly the system can respond, and how believable the pacing feels to users.
For product teams, the real question is not whether a model claims full-duplex behavior. The more important question is whether that behavior improves a concrete workflow such as discovery on a website, support triage, or guided rehearsal.
That is why most commercial demand around this category lands in voice agents, roleplay training, and operational surfaces that must stay understandable before the voice layer even starts speaking.