No to all points. Learning C++ doesn’t prevent you learning Blueprint (and if you know C++, you should know Blueprint pretty well at that stage anyway), any programmer should try to learn both as best as they can.
Additionally, the BP to C++ converter won’t work as well as everybody seems to think it will. It literally does dumb copy-paste from the engine source files. In most cases it will still be just as slow if not slower. If you want the utmost in performance, learn C++ properly.