I did read articles on medium about algorithmically adjusting coins but it does not make sense to me.
The proposal is to limit either supply or the demand of coins which will (in theory) adjust price and keep it stable.
However the actual pricing depends on the buy and sell orders for pairs which use the stablecoin on exchanges.
After giving a stablecoin to a trader in exchange for fiat or ETH for ex., the only way the issuer of the stablecoin to keep it stable is to actively trade the fiat/ETH to preserve the value and be able to return fiat/ETH when requested.
What matters is if the issuer of stable coins is capable of returning the total amount of fiat/ETH if all coin holder want to exchange back the coin.