Why we can't choose the Best Answer when a post is closed?

Before, it was the author of the question who closed the post by choosing the Best Answers! It was a good way to do it, which required little moderation! When the author of the question got tired of receiving emails for his question, he would accept a comment as the best answer and that would close the post.

It would be nice if now, even after the post is closed, we could choose a Best Answer and send reminders to the author of the question to come and choose one.

What do you think about that?