My extended family uses it to communicate. You can text and put pictures and videos on it. Personally I don't really like it that much though.
It does use Internet data if you're not connected to wi-fi. With my phone, I can choose to turn data off, and then it will only work when I'm connected to wi-fi. If you turn data off, you can be sure not to use any. I'm not sure exactly how much data it uses though. Probably depends on whether you post things like videos or just texts.