Understand that encryption is useless if 1 or more of the parties in a group is already compromised. That's the problem. Signal's encryption is great, but you are not anonymous in it. Additionally, even if, like me, you only use your handle and hide your phone number, most people tend to name your contact with your name anyway, effectively breaking the purpose. I use signal only because I'm sure my data is not being sucked as with WhatsApp, but I'm not dreaming for a second that someone will not fuck up at some point and give me away, so I keep stuff I don't want out there to personal interactions.