[jhasse]

It's not that easy: How would you exchange the private keys when using multiple clients? This would require to user to transfer the private key files or to remember a secure password. Both options aren't possible for usability reasons if you want to beat WhatsApp.

[_jomo]

This has been discussed a lot in the issue thread. Key exchange really isn't the issue.

Scanning a QR code or creating a secure connection between the clients to exchange the keys isn't that hard.

[jhasse]

What when I want to login at a computer but don't have my phone with me?

[chralieboy]

Same as using 1Password — you don't.

You're trading convenience for increased security.

[sherjilozair]

This is why it isn't 'by default'.