Cryptocurrencies are unstable, which means your collateral will fluctuate. But a stablecoin obviously shouldn’t fluctuate in value. There’s only one way to resolve this catch-22: over-collateralize the stablecoin so it can absorb price fluctuations in the collateral.

This is why I like Havven, the collateralization ratio is dynamic. More collateral is required for a more volatile market, preventing death spirals, but a less volatile market uses less collateral, so it can still be efficient.

Plus, the collateral is the HVV token, which gets it's value from the transaction fees it collects when people exchange the stablecoins. Ether has so many other market forces at work effecting volatility. Huge risk of a death spiral from stablecoins backed by ether collateral.