Well you will still be exposed to bitcoin volatility whether your hold bitcoin or BitBTC, with that being said you will gain speed and also the yield.
Pegging to BTC is pegging to a roller coaster.
Pegging to USD is pegging to a nice gentle glide slope ... until it isn't.
Pegging to GLD is pegging to whatever the paper gold manipulators want it to do.
Best bet is to peg to your favorite mix.
Stability depends on your time scale.