With IPv4, it's almost assumed you are behind a NAT, especially for a wireless device.
And this has caused many problems. ICE / STUN, TURN, UPnP-IGD, NAT-T, and the whole swath of fixes to the problems created by NAT stand as a testament to this
Most home routers don't NAT for IPv6.
That's because NAT was an ugly hack and IPv6 was designed in part to fix the brokenness that necessitated it.
The NAT added a decent layer of security.
Only as an accident, and not one that should be relied upon in place of real security measures
Ditching that security, as well as making your packets bigger for a wireless device, just seems stupid.
The benefits far outweigh the consequences of a slightly larger packet header, and there is less processing the router needs to do (and less state to hold), so the routing is more efficient. And if the device implements a simple soft firewall (as almost all IPv6 compatible SOHO routers seem to be doing nowadays) you're only better off for using the right tool for the job.
And this has caused many problems. ICE / STUN, TURN, UPnP-IGD, NAT-T, and the whole swath of fixes to the problems created by NAT stand as a testament to this
That's because NAT was an ugly hack and IPv6 was designed in part to fix the brokenness that necessitated it.
Only as an accident, and not one that should be relied upon in place of real security measures
The benefits far outweigh the consequences of a slightly larger packet header, and there is less processing the router needs to do (and less state to hold), so the routing is more efficient. And if the device implements a simple soft firewall (as almost all IPv6 compatible SOHO routers seem to be doing nowadays) you're only better off for using the right tool for the job.