Scalability: vSRX instances can be easily added or removed as the needs of the network change, making it a flexible option for scaling in a software-defined network. Granular Security: vSRX allows for granular security policies to be enforced at the virtual interface level, making it an effective solution for securing traffic in a software-defined network.
The two benefits of using a vSRX in a software-defined network are scalability and granular security. Scalability allows you to increase the number of resources available to meet the demands of network traffic, while granular security provides a level of control and flexibility to your network security that is not possible with a traditional firewall. With a vSRX, you can create multiple levels of security policies, rules, and access control lists to ensure that only authorized traffic can enter and exit your network. Additionally, you would not require a software license to use the vSRX, making it an economical solution for those looking for increased security and flexibility.

https://www.juniper.net/documentation/en_US/junos/topics/topic-map/security-chassis-cluster- data-plane-interfaces.html