Peer review is just another thing that helps individuals decide scientific matters for themselves.

The implicit idea behind peer review can be summed up like this: "This is what I think about this work. (I have credentials X, Y, and Z, and I've published this stuff you many have heard of.) What I have to say is just another thing for you to consider. Take it or leave it."

It's more than that as it's vary possible for things to fail peer review and or be edited and resubmitted. But, also in some ways less as you as a reader don't know who did the peer review.