Recently, a lot of people are talking about secure messengers like Signal. I, personally, like Signal messenger. The idea is very great and this is what we need as our primary daily communication tool, if we set encrypted email aside. But the thing is having a mobile phone with cellular data or Wi-Fi on is dangerous for our privacy.
Carrying a mobile phone with ourselves can lead to us being identifiable. Our mobile phones, specially smart phones, can actively spy on us. However, if you need your smart phone, I suggest to switch to messengers like Signal.