Why is this design the best remote access design for the environment?

Providing redundancy in case of appliance failures (e.g., via HA pairs) is critical for high availability of remote access services. Minimizing internal WAN traffic is achieved by routing users to the closest or most appropriate datacenter/appliance, thereby optimizing network performance and reducing bandwidth costs within the internal network.

While site redundancy is important, this answer specifies 'optimizing external WAN traffic,' which is less about internal WAN traffic minimization and more about egress optimization.

Protecting against WAN failures typically refers to external WAN links, not necessarily internal WAN traffic, and doesn't explicitly mention appliance redundancy, which is a key part of the chosen best design.

While scalability is a desirable characteristic, it describes the ability to expand, not the specific benefits of redundancy and traffic optimization that make this design 'best' in terms of immediate operational efficiency and resilience.