That’s great BUT… what you really need is a responsive website not (at least) two native mobile apps.
Advantages: Reduced development effort, fewer maintenance costs, and pretty much the same benefit – which is accessing stack exchange websites on smaller screen devices. By entering the native app world your building all from scratch (some people are already asking about what will happen to LaTeX characters on these native apps).
You don’t even have to make it fully responsive, just let the questions/answers' text wrap according to the window’s width.
Scenario: a developer using a 13'inch laptop, half the screen with browser opened on stackoverflow and the other half with the code editor. This group of people will continue to endure the pain of horizontal scrolling or window switching all day long. What do you have to say to these people?