Traditional and old-fashioned as it may be to some, the cost, time, and thought involved in writing a handwritten note always add a touch of luxury to your message.

From the Harvard Business Review:

Personal written notes grow rarer by the day. But if you want to convey to a client, a potential customer, a colleague, or a direct report that you value your relationship, put down the Blackberry and reach for a pen. Emails, tweets, texts, or Facebook messages are easy to write and free to send. Handwritten notes mean more because they cost more. Drafting an actual letter involves selecting stationery, paying for stamps, and visiting a mailbox. They let the people know you appreciate them enough to pause for 15 minutes and put pen to paper in an attempt to connect and sustain a relationship with them.

from: http://blogs.hbr.org/cs/2013/04/handwritten_notes_are_a_rare_c.html