...bitUSD is 2x collateralized by BTS value...

And what BTS is valued in?

Correct, in US dollars. Therefore "bitUSD 2x collateralization by BTS value" is a meaningless expression because once the dollar value of bitUSD evaporates it won't matter how many times something is backed by zero.

And there's something else. Markets always deal with perceptions as suppose to real stuff. Therefore if you create a currency which is a stealth representation of the USD then you committing a grave sin of the unauthorised USD printing and no authority in the world will tolerate its currency counterfeiting.