Paper money is more durable than electronic money. Obviously, you cannot accept electronic money any place that is not specifically set up to take it, or when power or internet is out. I'm not sure you'll ever eliminate physical currency for that reason.
I agree with you, especially in my country there are many place that hard to get internet. So paper money very usefull on that place. I think paper money will permanent in some place.
The paper money is going to stay for a little longer I believe, it will not disappear so quick they also do not need to force it.
When the time is right the paper money is going to disappear.