Google has made some changes to its developer policies, and banned further app classes from being submitted to the Play Store. These include apps that mine cryptocurrency, apps that facilitate the sale of weapons, and apps that replicate other apps.
The cryptocurrency app change refers to apps that are specifically used to mine, and apps that remotely control mining are still allowed. This follows a similar ban of mining apps from the Chrome extension store.
Apps that provide the same experience as other apps available are also banned. Google says examples of this include copying content from other apps without adding original content of value, and creating multiple apps with the same user experience. Google suggests developers create a single app that aggregates the content instead.
Similarly, apps that exist only to serve ads are banned, for example by placing an interstitial ad after each action. Apps that are designed to help users purchase firearms, provide instructions to make ammunition, or convert weapons to automatic/semi-automatic are also not allowed.
Google’s updated developer policy can be read in full here.