I also love reading writer interviews in magazines like Mslexia and Writing Magazine. I always learn something. And I have found interviewing my own characters has been a great way of really finding out what makes them tick and would highly recommend doing this for any fiction writer. Such interviews could of course make for good posts on websites as a great way of giving your readers extra information about your characters.
More importantly I have found such interviews have made me think much more deeply about what my characters are all about and I believe I now write for them/about them with more conviction. I think that conviction shows in confident writing. And that you can't fake. (Well I don't think you can. I know when I read something that really grips me, it usually is down to the strong characters and that tells me the author has done their homework. Perhaps part of that homework was their own interviews with their own characters before they started writing the story in earnest. Let's just say I wouldn't be surprised if that was the case).
So interview away and have fun finding out more about your characters. It is bound to help you write about them with more depth.