Ability to have a separated TCP/IP stack with "ip netns".
It allows using overlapping ip addresses/binding ports for different virtual networks, etc.
https://man7.org/linux/man-pages/man8/ip-netns.8.html
https://iximiuz.com/en/posts/container-networking-is-simple/
https://medium.com/@abhishek.amjeet/container-networking-using-namespaces-part1-859d317ca1b8