So the reference models included in TOGAF (TRM and III-RM) are, to be honest, not entirely useful for much. They were included to show what the concept of a technical reference model is.
Reference models are just very generic, easily adaptable, ways that you can structure your software designs. TRM, if you look at it closely, is VERY generic and can apply to almost anything. It's basically describing applications sitting on top of a communications network. That could be anything. That's why it's Foundation Architecture. Foundation Architecture in the Enterprise Continuum is the most generic reusable components of your architecture.
The III-RM is said to represent a more provider-consumer type model (client server for instance). But even then it's very generic and needs to be tailored to your company before it can be used. It's an "Common Systems Architecture" in the Enterprise Continuum classification.
So I cannot agree with the statement "their purpose is to structure the Enterprise Continuum". Better to say that they are example architectures that can be classified as completely generic (Foundation Architecture) and mostly generic (Common Systems Architecture).