Security inefficiency is not an excuse to hold someone's BTCD for 48 hours. It's already quite established crypto. Other major exchanges don't have problems with withdrawals. They process them immediately
I wouldn't necessarily call what bitjon was describe as inefficiencies, but rather precautions that would protect your money at the end of the day.
IMO it is a good thing for a withdrawal to take a long time when a third party controls the private key to your coins. The longer it takes them to process a withdrawal, the longer you will have to stop it in the event your account is hacked