Hackers target smartphones to mine cryptocurrencies

But Google recently cleaned up its app store, Google Play, telling developers that it will no longer accept apps that mine cryptocurrencies on its platform.

"no longer". Meaning that it was previously aware of these apps but accepted them anyway.

It's not so sinister as they make it sound. It's a way of monetizing an app without intrusive ads. Obviously the problem is that you know when there is an ad, while this is done secretly in most cases. It also eats up computing power - which would be OK if you were warned of it first.

It's also a net positive that Google play offers so many apps, unlike Apple's walled garden. The downside is that, like in any free market, you have to be a little careful in what you download.