Most people in the world don&#x27;t (or barely) use email, specially in EMs. Also, you can access you email from many different places, you (usually) can&#x27;t receive an SMS on the same number from many different places.<p>Another advantage of using phone numbers is that people actually have other people&#x27;s numbers in their phone address books, which whatsapp uses. Very few people have their friends&#x27; email addresses on their contacts.