This is designed to make Signal more popular while solving some fake account issues: - Using phone numbers means that Signal can constantly check against your

This is designed to make Signal more popular while solving some fake account issues: - Using phone numbers means that Signal can constantly check against your contacts to let you know if any of your contacts are now using Signal. As such, using phone numbers encourages use of Signal. - The usage of phone numbers instead of email or usernames also helps combat temporary/fake account creation abuse, as phone numbers are KYC if you ban VoIP numbers That said, in the end it is a compromise on privacy and anonymity to increase the popularity and stability of the app.