Having the breathing room is great.

You have two teams that independently set up private networks but now someone has to talk to them both?

In IPv4, they likely stepped on the same private subnets. In ipv6, they pretty much certainly did not step in the same ULA prefixes. My VPN setup is a mess of a maze to deal with the fact that most things I connect to are all independently allocated 10. subnets, with the IPv6 focused customer being easiest.

Also, if you want to embed information in your addressing, like vlan I'd or room information.

Besides, you can have addresses like fd37:5f1a:b4c1::feed:face, and that's fun isn't it?