I dont see any reason why people would want to pay extra for a built in PSU. Anyone doing mass upgrades from the S9 already has power supplies, most likely of a higher quality than the ones that come built onto miners. I know the last thing I want is another proprietary part in my datacenter that I cant just switch out on the fly.
if it is all they sell you will have no choice.
the more i think about it they will do a 40th unit using an attached psu
getting 48 to 52 watts a th.
sold at 950 to 1050 it kills everyone price and efficiency wise.
and forces you to buy it with the psu attached, since the psu needs to handle about 2100 watts.