Are “extras” a good idea?

Some years ago, I was asked by my publisher to write an extra section, to be added to the end of my novel. See my Julia page on my web site.

Do you favour this idea? It was new to me (as an author writing in the UK).

I do add a section at the end of each novel, mentioning my other books, with a short explanation of what they are about.
I hope that this is helpful to my readers, but what is your view?