Re: IPv6 not that hard... seriously
Because you need v6 to reach v6 servers. If you don't know at least that much then you're not in a position to comment on this stuff. v6 also lets you sidestep all of the problems caused by NATing, which is another strong reason to be using it.
The energy cost of NATing (and subsequently recalculating the packet checksum) is worse for the environment than the few extra bytes in the header. The energy cost of the routers, servers and client machines involved are orders of magnitude worse however, to the point that worrying about a few bytes that are <1% of the packet size is utterly silly.