Prayers by the Pen

I've taken part in a short discussion lately on the practice of writing prayers to be read publicly. Growing up, I got the idea that writing prayers was something the heathen churches did and that writing out your prayers to read in public wasn't sincere. You should pray extemporaneously "from the heart."

In response to that argument, let me ask a couple questions. What is different about someone calling you up on the phone or writing you a letter? Is one method of communication sincere and the other impersonal?