Each person has their own personal font when they write by hand. Your hand writing is perfect in its imperfection. Only you can write in your personal font .
Your hand written font is what makes the letter organic. No computer can recreate or copy what you have made because each letter is unique. Your hand writing is your own personal brand.
When you write by hand you are giving people an opportunity to use your spoken voice to read the written words. Your written voice comes from the history of interactions you have had with the reader of your letter. An email or a text, even a typed letter, lacks the personal depth of your voice. When you write by hand you are speaking those words to the page. Your voice will play in the person's head when they read the letter that you wrote.
Hand written things implicitly say, "you are worth the extra effort." Writing things by hand costs you, but it also says something about the person for whom you wrote it.