Unless your app is a social app, and even then I'd integrate messaging only if it's a core ability.
At work, the team that was responsible for the app before I came along, 12 years ago, wanted to integrate a messaging ability into our internal company app.
I was literally shocked when they told me that, since that it reflected such a disconnect from reality, reality being the app was extremely crashy, not documented, and filled with bugs, and a disconnect from what users really wanted (I'm a former user turned core dev) that I couldn't even believe these people were for real.