NAT'ing sidestepped the short term problem of IPv4 numbers running out, so for now it'll be safe for you to disable it.,
It didn't solve the long term problem, which as I understand it has resulted in China turning almost exclusively IPv6, but as the IPv6 was designed to coexist with IPv4 you probably don't have to care about that for the immediate future.
Reductionist and proud of it.
Being ignorant is not so much a shame, as being unwilling to learn. Benjamin Franklin
Chase after the truth like all hell and you'll free yourself, even though you never touch its coat tails. Clarence Darrow
A person who won't read has no advantage over one who can't read. Mark Twain