The prizes have some credibility, of course. And they do good work for the writer and for the publisher, by winnowing one book out of the pack.
We know that people we love are both good and bad, but we expect strangers to be one or the other.
What I am finding now is that my audience is getting younger as I get older, which is a very good thing as you know - you don't want them to get older as you get older.