and that advantage goes out the window with stateless one-to-one #NPTv6 so what's the advantage over stateful one-to-many #NAT66... considering YOU NEED A STATEFUL FIREWALL ANYWAY...

As I've talked about before, a problem with #ipv6 is that when your prefix changes, you have to update all your config. My prefix from xfinity changed and I had to manually update all my static DNS, firewall rules, wireguard configs.. The "correct" solution to this seems to be #NPTv6, but #Mikrotik doesn't support it. So it's tempting to just do #NAT 66 and have it work the same as #IPv4.