[Blaaguuu]

Previously you could only write code for the Unreal Engine with C++ or the visual scripting system, Blueprints. This allows people to use C# for everything that they would normally need C++ to add to their games - which will particularly help with people who are trying to transition from Unity to Unreal.

[Arwill]

UE3 had UnrealScript, a VM based scripting language, similar to Java or C#. It is odd, that Epic removed it in UE4, and now someone makes it as plugin.

[SXX]

There was one good podcast (that sadly not in English with) Nick Atamas (senior engine programmer in Epic).

They had serious reason to not provide any official scripting support in UE4. Basically there no single language and runtime that would work well across all platforms: between Python, Node.js, Mono none of them work on every platform Epic target. Some don't have good support for consoles and other for mobile platforms and maintaining fork is hard even for Epic. So instead they try to extend blueprints instead since for them there are no such problems with C++.