I am not an expert, but it seems that regular C++ wins every time as far as speed and flexibility within the engine. If you get deeper into your project there will be times when C++ is the only way to manipulate or extend some things. I tried nativizing an entire project a few times, and the load times reduced dramatically in a blueprint only project. Nativizing still seems to be in early stages as it can break random things so I would just use the exclusive mode and test it with individual blueprints that are math heavy or used most often. Here is an example of how fast it can speed up crazy stuff on tick.
