They have 1-5 million installs.
Never tried it - but once 'easy money making' tools are easy to game, they lose their mojo. In this case, seems like the money part was badly executed (am going purely by the ratings, i.e. 3.8).
For products like these, the number of installs isn't the right metric to look at. Everyone wants 'free money' and people will download - what would really matter is whether they are able to make some money or not. And if not money, whether they are seeing other benefits in using the product or not.
In this case, it seems there wasn't any other benefit.