The minutes should simply deepen and expand the rationale for a policy decision that was already given in the statement released immediately after the meeting. They might also indicate the existence and strength of contrary views. At the margin, some of this might be additional information.
However, there is a risk that even such a marginal expansion of information could receive more weight than it warranted and foster misperceptions about the possible course of policy. Such misperceptions might result from a market misinterpretation of any one element of these minutes, which in turn could lead to an inappropriate reaction to incoming data.