It's not much of an oversimplification to say that the public wants lower taxes, more spending on the programs they like, and a balanced budget. Congress can't balance the budget without raising unpopular taxes and/or cutting popular spending.
State legislators who pick delegates to a ConCon and then vote on whether to ratify an amendment are under no such constraint. They can get the best of both worlds. "See, I'm for fiscal rectitude, I voted for the balanced-budget amendment!" It then falls to someone else to implement it, with resulting loss of popularity.
In the ultimate irony, a Senator or Congressmember who votes for the unpopular measures needed to balance the budget might then be successfully challenged by a state legislator who voted for the amendment that forced that unpopular action.
I can't see ratification by 3/4 of the states for something like outlawing abortion. The 13 most liberal states could block it. I also think Wolf-PAC's efforts are wrong, because the 13 most conservative states could block an amendment to overturn Citizens United. The balanced budget, however, wouldn't be strictly liberal-versus-conservative, but would also be state-versus-federal. I can see quite a few Democratic state legislators voting for it.