Yes this, for a while it seemed the IPv6 hated the thought of an IPv6 RFC1918 equivalent. I've seen a lot of people say with the gazillion IPv6 addresses you would get, you can use them internally.

No

I don't want my internal network to have our IPv6 address from our ISP. An ISP can change your IPv6 address at any time, they could go out of business, they could be acquired, etc. Then what? I have to change the internal addressing for the entire company? Nah. The IPv6 address from the ISP can exist on their side of our demarcation point. I'm not going to number things internally if that number can be revoked.