Novelty, as said below. Also, it removes a possible level of distraction. It's harder to get distracted when you go right from the mailbox to the kitchen table

Novelty, as said below. Also, it removes a possible level of distraction. It's harder to get distracted when you go right from the mailbox to the kitchen table with a pad and pen than it is when you have to open an email and avoid switching to your other tabs.