NEVER Invest in this money milkers
At first everything seemed to be legit. You could earn bitcoin, they paid out at a certain amount of mined bitcoin. Legit. Only 10 ads no decreasing earning mechanic. So you start to invest more cash. After this they changed more and more their behaviour. Instead of 10 ads you have to watch 30 and they implemented an daily decreasing mechanic when you don't watch ads you lose 1% every day. It adds up. If you watch ad they doesn't work proper (intentionally) and so you don't get the revenue because the owner take away your bonus and say it's your internet problem. I invested 900€ over half a year now and only got back 350€. Google play store reacted and banned them from their store. Pls don't be greedy like me and NEVER invest!