We live in an age of email spam, bulk mail and automated telephone calls. Receiving a handwritten letter or note is rare. When we do receive one we know someone has taken the time to think about us specifically.
We wanted our workers to know we were dedicated to them and had belief in them, so they would be dedicated and have belief in themselves. This is why we trained our first-line managers (and the rest of the staff) to recognize people with handwritten notes.