How he's describing it is new to me but I think it makes a lot of sense. What he's describing is a business layer written in whatever language the backend team wants (likely different from the frontend team). The backend is not concerned only with the web client, their code can be used for a variety of internal and external clients. Then the frontend team can use Node, they're already hired based on their JavaScript expertise, as the UI layer.

It makes a lot of sense. With services architecture the backend team shouldn't be concerned with the web client but because of historical reasons this is typically how things work.