I believe there are good arguments for why it shouldn't. The answer is that e-mail is often more efficient. I can draft and send an e-mail message in a fraction of the time it takes to send a letter, and I can include computerized documents by dragging and dropping an icon into the message body. Also, the e-mail message arrives relatively quickly. By contrast, letters typically require secretarial and other office assistance, and if I want to include draft documents in computerized format I must include a diskette.
Letters take at least a day.
There are alternatives - facsimile and voice mail. However, sending documents over the facsimile machine requires almost as much effort as sending them through the mailbox. So, for many exchanges e-mail offers lawyers and clients a better way to communicate. While there is some truth to this perception, much of it is based on hype. Computer criminals exist, and they can cause and have caused a lot of trouble.