The main reason to chose snail mail is not that it is slow, but that it shows some amount courtesy and appreciation.The cost (in terms of time) of writing an email v/s letter should not be measured in terms of the number of minutes. I think of it this way, somebody who had take the time to get some postal envelops, stamps, sat down and wrote the letter leaving his work in some way and then dropping it off to a post box is much more classy than someone who composed an email in his/her already open client and wrote a bare bone email with a template in their drafts folder.