Why do you no longer accept entries by regular mail?

Almost the entire publishing industry has gone digital until a book is in print. It is a much faster and more efficient way to communicate and transfer documents and files. It also saves paper and trees. Writer’s Edge reviewers also live in various parts of the country, and “snail mail” is no longer an efficient business practice.
You, as author, will need to use email systems and word processing systems anyway, since virtually every publisher today requires it.