ipv6 was designed for global addresses used on the global address namespace. The community hates anything not doing that since that would remind too much of NAT

ipv6 was designed for global addresses used on the global address namespace. The community hates anything not doing that since that would remind too much of NAT. So anything intentionally not on the global namespace is second rate and not quite supported*. Alas, being on the global namespace means being dependent on your ISP** - what if they renumber or you want to move ISPs? - or going through the bureaucracy of registering your own block. Yes, despite an infinite space you still need to register to avoid fragmentation. That's something I never want to do. * For example, IPv6 ULAs have a stupid lookup precedence - IPv4 addresses are higher which means ULA can't be used anywhere which is dual stack. ** There are ways around the latter like ULAs (see above) or using a local DNS (more mess if it fails, assuming everything supports this), or NPT - which would work, but again, the community hates anything that reminds of NAT even when it's totally stateless, so this is little documented. I don't think going against the entire community is a worthwhile endeavor. This should also limit your choice of routers since IIRC not everything supports this.