It also use for wireless keyboard/mouse.When its come to update/upgrade, Acer always were the first. NO complain so far.Unlike Galaxy Tab that has no port and no reset button.
Since the OP put most of his content into the title, Its hard to speculate on what he meant or even what
the purpose of the post was.
But I think he suggests you can charge something else by plugging
it into the full size USB port. Didn't read that as charging the tablet itself.
Might be an option if your cell phone is totally dead and you have no wall outlet around
but your tablet battery is full. Can't say as I recommend this practice.
Icebike you could be right.
While you can power things from the usb, like a portable drive, can you actually charge it. unless you have the tablet charging, all you would be doing, if possible, is drain the tablet in the process.