Fundamentally actual E2EE is complicated problem. And probably not very user friendly. It is full of technical trade-offs. And mistakes are very common. Or they lead to situations that people do not want. Like if you lost your phone or it break how do you get history back... What if you also forgot password? Or it was stored in local manager...

It is phrase that sounds good. But actually doing it effectively in way that average user understand and can use system with it with minimal effort is very hard.