A Washington Post article on the future of the Consumer Financial Protection Bureau (CFPB) contrasted the arguments of supporters, that the CFPB has protected consumers from unethical practices from the industry, with arguments by opponents that it has hurt lending. (These arguments are false, small businesses report they have little trouble getting credit.) The discussion left out the economic efficiency story for the CFPB.
The basic story is that if it's possible to make lots of money by using deceptive contracts to ripoff consumers, then many very talented and hard-working people will spend their time developing schemes to ripoff consumers. Instead of doing things that contribute to consumers' well-being (e.g. developing better products), these people will be committing resources to redistributing from others to themselves. If the government makes it more difficult to profit from the ripoff route, then people who want to make lots of money will be forced to turn to productive routes instead.
By this logic, weakening the CFPB, and other measures designed to protect consumers, gives more incentives to businesses to design elaborate ripoff schemes. In addition to being bad for consumers, this is a waste from the standpoint of the economy as a whole and a drag on economic growth.