Developers can create apps that can change the way that smartphones are used. The apps that they create can add new features to phones and revolutionize phones. All apps are not created equal. Some apps add nothing of value to the phone, may add features that are useless to those that download them, or even have features that can be taken advantage of that can harm others.
These apps are often removed from the app store, be it from the Apple App Store or the Google Play Store. New rules may have to be created to remove some of these apps because of their harmful nature. Sometimes the apps can sneak by regulators. Other times public outrage causing apps that were previously seen as fine to be taken down.
The apps can be useless, serve no purpose, or have nefarious purposes. Often times they're just money making schemes, from useless apps worth $1,000 to apps that do nothing but simulate a knife noise, the apps are just useless.
These apps can be controversial, developers of these apps have no regard for the feelings of others as is the case in a couple. Taking a controversial topic and using it to make money is not a good business model.
