in reply to Why is $$var bad?

This article discusses the answer to this exact question.

It is indeed a very bad idea.

You think you want to be able to write $Email instead of $form{Email}, but there's a tradeoff there. The cited article discusses that tradeoff, and points out that it's a really bad move. On the bright side, you get to save a few characters typing. On the dark side.... Well, it's too horrible to go into.