Use Matrix if you want to contribute to Matrix or are an enthusiast about what Matrix is trying to do. But don't use it as a secure messenger, or tell at-risk people to use it. It may someday be a serious option for secure messaging, but it is not that today.

I'm not a Matrix hater, but I think Matrix's cheering section gets the project in trouble, since their answers about privacy and security are demonstrably worse than those of other secure messengers. All Matrix is trying to do is build a modern, generalized IRC with optional built-in encryption, which is a project congenial and relevant to my own interests (my only funded startup tried to do the same thing!). That's great, as long as you're not trying to get people to use it to hide things from governments.