What would be the negatives to using custom cut mirror glass as a top for furniture, as opposed to regular glass?

I have a wooden night stand that I am going to repaint, and in order to keep the top from getting scratched, I am considering getting a custom cut piece of glass for the top (nightstand is a weird shape so glass has to be custom done). I am also thinking of using mirror glass instead of regular glass.

What would be some issues of using mirror instead of regular glass?