IPv6 isn't just a larger IPv4. There are features inherent to it, like link-local actually functioning and being predictable, unlike APIPA in v4 which was grafted on as an afterthought and breaks more than it works.

It also functions router-less. You can grab 30 10-port switches and just stick them together and start plugging computers in. It will work without configuration or an authority.

I am all v6 internally, but that's not because I have a splatillion devices, but rather it's just better and easier to manage.