[citation][nom]Blah_Blah_Yadda_Yadda[/nom]Yeah, USB carries 5v on two of its lines, but according to the spec, devices can draw no more current than half a watt. That's not a problem for smartphones, but it's kinda inconvenient if the device you're trying to charge has a big monster battery.The point of the Lightning port was to replicate the functionality of the 30-pin connector using a smaller, all-digital form factor. Sure USB is programmable, but it's also slooooow. Until USB 3 is available in a mobile device-friendly form factor, it will remain too slow to handle high-bandwidth applications like high-def video.[/citation]
According to the wiki, USB 2.0 supports up to 5 amps of 5W for charging. That's 25W. Furthermore, high-def video isn't normally run on USB, so I fail to see your point there. Regardless, USB 2.0 supports up to about 400Mb/s of practical throughput and usually tops out at about half that. Around 200Mb/s is around 25MB/s. That's fast enough for HD video and regardless, it's fast enough for any use of USB with smart phones and tablets. Would USB 3.0 be better? Maybe, but USB 2.0 has thus far been plenty.