Essentially, a blueprint makes everything in the game logic clear and easy to follow. When creating a game with UE4, a blueprint does exactly this: makes writing code or game logic much easier.
If you have had the chance to work with the free, limited version of Unreal Engine 3, which was UDK, you will know that the scripting inside UDK was based on one of two things: either using the scripting language called Unreal Script, or using Kismet.
The Blueprints system in UE4 is almost the only, and certainly the most common way to build game logic efficiently and fast. It is the new version of the old system in UE3 called Kismet, that was not efficient when it came to refactoring the logic for different levels inside the same game. The engine supports C++ game code as well, but in that case I would not consider it as scripting, as C++ cannot be a scripting language and is pure programming!
With a simple graph of four nodes like the following one, you will be able...
