I repeat, the only real photo of the backside of the unit is this:
looks like a US plug tucked away there at the side...why do we need an extra usa adapter for $1 usd then?

It looks like a pair of fold-away metal prongs. BLADED prongs, parallel to eachother.
Bitmain's own pictures of the front show slight dips in the case where prongs would likely fold away.
It seems safe to say there are built to fit a typical US outlet format, without grounding (common for most small electronics).
whatever, i ordered 2 of them anyways

Pretty sure that is just the standard chinese plug, not sure what voltage it runs or how safe it is to use in an American outlet.