The big advantage of NATS protocol is that most terminals which is placed in residential network as using private addresses can work NATS protocol with no-support NATS.
NATS specification also defines some behavior of NATS router. In this definition, there is 'DNS query hook mechanism'. In this mechanism, NATS router have to hook DNS query from terminals which is placed in residential network, and the NATS router make a new query to resolve sub-address, and send it to appropriate DNS server. By this mechanism, NATS non-support terminals can connect to the other NATS terminals.
Furthermore, in case of connecting from the Internet to residential network using NAPT router, people have to configure NAPT router for binding received port with destination host. It is called 'static NAPT' configuration in general. In this case, if many web server are placed in one residential network, port number 80 which is known 'well-known port' conflicts among the Web servers.
NATS specifies sub-address in addition to IP address. Then, port number can use for each sub-addresses. It means if people use NATS, port number never conflict among servers.
Finally, NATS can support most of connection using the Internet Protocol. Because NATS enhances address translation process using sub-address, it does not depend on application software or other protocols. It might be the most advantage of this protocol.