Is it bad to use Blueprints to build the program from little c++ functions?
So e.g.: There are a system in blueprint with macros (which has functions in it) and functions that has more functions in it and stuff like that. Is it better (in terms of performance) to create most of the functions in C++ and call it from blueprint?
By default you cant make a child Actor component which was created in c++, only if you change the things in the header. So is it bad to create an Actor Component in Blueprint, which is a child of a c++ Actor Component and then use the Blueprint Component?
no, it is standard practice, i mean all blueprints are extensions of C++ classes.
Way blueprint works on the back is when you spawn blueprint in creates object on C++ side of class of highest parent (one that lowest parent of blueprint inherented), and C++ code generated from things like BlueprintImplementableEvent and such when called redirects code execution to blueprint virtual machine, so blueprint is used only (so it performance penalty) when code from it is executed the rest is native code, there no extra penalties for instance of blueprint to exist (other then bit more memory used per bleurprint class involved?)