Yes, flexibility. You don't need to have 2^24 hosts for a 24-bit address space to start becoming cramped. You have to divide up that space into subnets that rou

Yes, flexibility. You don't need to have 2^24 hosts for a 24-bit address space to start becoming cramped. You have to divide up that space into subnets that roughly match your physical network structure, which depends on accurately anticipating future growth; otherwise you'll have to suffer the pain of renumbering later on. The real benefit of a /48 or /32 IPv6 subnet isn't that you never run out of individual addresses. It's that you're practically guaranteed never to run out of identifiers at any level of the hierarchy.