Since you can have multiple IPv6 addresses on one machine, you can use a rotating address for all outbound connections and a permanent address for inbound connections. If you visit a malicious website that tries to attack the IP that visits it, there will be no ports open. They would have to scan billions of addresses to find the permanent address. All of that scanning would be easily detected and blocked by an IDS.
Since you can have multiple IPv6 addresses on one machine, you can use a rotating address for all outbound connections and a permanent address for inbound connections. If you visit a malicious website that tries to attack the IP that visits it, there will be no ports open. They would have to scan billions of addresses to find the permanent address. All of that scanning would be easily detected and blocked by an IDS.