The BitUSD/BTSX peg is not super tight because people are bullish on BTSX as a result it may peg below the dollar and not a lot of BitUSD may be created.
Also BTSX is currently quite volatile, low liquidity and can potentially be manipulated by the exchanges. BitUSD will have a wide peg at any time based on bullishness/bearishness.
What about gold pegs? G-USD/Gold
G-USD can be created by people shorting not based on the price of BTSX but on the price of gold.
This is far more stable less volatile. This peg will be super tight
If you are bullish on dollar vs gold you go long or if you just want G-USD (for the same reasons people want BitUSD but G-USD more stable I think) If you are bullish on gold vs. dollar you short. When two trades meet G-USD is created.
It should work exactly the same except a G-USD will always get you very close to a $ worth of BTSX because the gold/dollar peg will stay very tight unlike the dollar/BTSX peg which has the problems cited above.
We are pegging around the gold to dollar even though the collateral is still BTSX vs. pegging BTSX to dollar.
It's 3am here. I'm sure there's a simple reason this couldn't work just putting it out there