After the collapse in 2008 we learned that such regulation is necessary to protect consumers from losses and banks from criminal specualtions. Because this regulatory act was dismantled we are finding ourselves in this current Depression.
Preserving Glass–Steagall will regulate :
Conflicts of interest characterized by the granting of credit (that is to say, lending) and the use of credit (that is to say, investing) by the same entity, which leads to abuses.
Depository institutions that possess enormous financial power.
Securities activities that can be risky, leading to enormous losses. Depository institutions that are supposed to be managed to limit risk. Their managers thus may not be conditioned to operate prudently in more speculative securities businesses.