Words convey information: that’s important to me.
Words, strung together in sentences are information vehicles driving thought from one person (me) to another (reader): that’s important to me. The nature of verbal communication is to transfer the information via the ether, with syllables of sound; if there are no ears to hear, the words disappear. The communication falters. If words are passed orally to another, the communication is received but the information is now reformulated through another vehicle.
Written communication addresses the weakness of oral communication.