The parent talked about signing up for Signal requiring a phone number. The following point is tangential from that after the signup is completed using a phone

The parent talked about signing up for Signal requiring a phone number. The following point is tangential from that after the signup is completed using a phone number. Signal Desktop is a standalone client that can be launched and used without having one's phone nearby or available or connected to the net. WhatsApp, however, requires the phone to be around and connected for the desktop app to send the chats through. From that perspective, WhatsApp actually offers a worse user experience than Signal.