I'm a developer and very confused


Trying to get your guys feedback on this:
In my opinion there are lots of people have vision problem, such as seniors. Or people who hate lots of icons and complex in android phone.
So I developed an app make things easy and simple, just like a function enhanced "Easy Mode".
The app named Large Launcher and get lots of downloading in Taiwan, but very limited download in US, mostly like around 20 downloads a day.

So, my question is:
1. My marketing strategy is working wrong in US market?
2. US people do really not need such an app like this?

Can you guys give me a little advise then I can improve the app or my marketing strategy?

Thanks a lot.

My app named "Large Launcher - Big Font, Text" and the download link: