You can withdrawal using the withdrawal tab. If there is a gateway that supports USD withdrawals you can do so there. I Sorry you feel it iis not user friendly. I read the opposite often!
Moving on, there are many Alts and other USer Issued Assets and gateways on the BitShares DEX.
The legitimacy and possibility for any altcoin alt project requires due diligence as it does on any exchange. In this unregulated space, the possibility for shit coins is evident. Various important BitShares developers and spokespersons are working with eX SEC lawyers in an attempt to create a security token exchange using graphene tech.
You can look that up at stokens.com I think.
Exciting times