I recognize its not a firewall like an iron door on your house blocking intruders, its more like the intruders don't know your address. But it is a layer of security help as per this quote from CISCO

"NAT is a networking feature that can help reduce organizational security risk by hiding internal networks from public networks. By default, outside public IPs cannot communicate to an internal private IP host if there is no pre-existing NAT translation. So, NAT separates public and private networks.

Additionally, organizations that use NAT can implement and maintain multilayer security to block threats and protect against malicious activity. Your edge platform may be able to perform these essential security services."