Especially in that disaster-recovery scenario, when you're figuring out how to combine the different namespaces that different disconnected fragments of the int

Especially in that disaster-recovery scenario, when you're figuring out how to combine the different namespaces that different disconnected fragments of the internet are using, you really don't want namespace collisions. Namespaces are abstract things that exist outside of the realm of actual network connectivity, and enable you to plan for all kinds of hypotheticals.