Blueprint is Unreal's visual scripting layer; C++ is the engine's native language. Both compile to the same output, but the choice affects workflow speed, runtime performance, and team composition.
- Blueprint suits rapid prototyping, designer-owned gameplay logic, and UI flows. Iteration is fast, but runtime overhead is marginally higher than equivalent C++.
- C++ is preferred for performance-critical systems: physics, AI, netcode, and custom engine extensions. Build times are longer, but execution is faster and the codebase is more portable.
Most productions use both: designers iterate in Blueprint while engineers own core systems in C++. The right split depends on team composition, performance targets, and how much logic needs to be accessible to non-engineers.