One of the downsides that needs to be addressed is the collateral requirements required by bitshares is significantly greater than what can be offered by centralized lenders.
It's difficult to utilize bitshares as a bank in this case, as one must put up a significant amount of collateral and the opportunity cost of utilizing capital in this fashion is too great.
To me, it still functions well as a way to short USD or CNY and to perform some level of forex trading - but utilizing crypto as collateral requires less volatility than is present in the current paradigm.