Allow other developers to easily use your app with your consent. This makes it possible for you to collaborate with many others to develop your application.
There are detailed documentation on the lines of code, purpose and how it works so that newcomers don't spend too much time to master the SDK.
Provide a full range of tools to maximize the use value of other applications, thereby helping your application to be more visible to customers.
Well-integrated with many other SDK tools to help your application work smoothly on many platforms without having to re-write code from scratch.
No harmful effects on the battery, GPU or devices on your computer.

Some popular SDKs: Android, IOS, Windows, VMWare, Facebook...