The EFC is not something anyone will be charged for. Like many of the government's ideas, it's not exactly the thing that it's explicitly labelled as.
The idea is, whatever the EFC, that's the amount that in theory the borrower could contribute out-of-pocket over the course of the year -- but it's not like anyone will be making you write a check for that amount. It is one of the figures that goes into figuring out your final FA award total.
Basically, if the EFC is high, the person gets little to no subsidized aid. If the EFC is zero, the person may qualify for more and better forms of aid, grants, and whatnot. EFC does not lower the overall total amount of FA available.