Hide And Show Variable In Property Window

Are the variables from a derived C++ class or blueprint only? I do not know if there is a fancy way to use UPROPERTY() in such a way to fit that need (probably some convoluted way does exist), but that sounds to me like you would want to change the behaviour of the editor itself, in which case you’d have to change the source code of the editor in the engine. Why would you want something like this?