If that is what you mean by default then yes Blueprints are generally preferred because they are accessible both by Artists and experienced developers. C++ is g

If that is what you mean by default then yes Blueprints are generally preferred because they are accessible both by Artists and experienced developers. C++ is generally preferred for performance reasons because Blueprints being an interpreted language is around 10 times slower ( these are estimates by Epic the creator of Unreal). Of course how much Blueprints will be used will depend on the game. There are games made entirely with Blueprints. Also Epic recommends the use of Blueprints as first choice again because of ease of use. They have invested a great deal to it after all. It even has a debugger with break points , watching values and visualization of execution flow.