Blueprint also does not handle any kind of file I/O, so that would need to be done in C++.
I do most of my work in blueprint and only when I encounter something I can’t do in BP do I move over to C++. Other situations are fringe and rare, like a blueprint bugging out or situations where performance is actually limited by BP. Again, these situations are extremely rare, but they do happen.
When I first started working with Unreal Engine, I took a Lynda course on C++ because all I really knew was Unity-level C#/Javascript. It turns out that this was never really necessary - outside of syntax differences between C++ and C# (of which there are few), Unreal’s interface layer for C++ is really, really easy to use. I toiled for weeks trying to learn vanilla C++ and it was hard. Very hard. I couldn’t get my head around a lot of it. I thought I’d be relegated to blueprints or Unity forever. But really, I never needed to learn about half the stuff I forced into my brain. I still run into some things that I have to guess at (like passing by reference for some things such as converting FString to FName) but it did not take long at all to transition.
I used GameMaker a lot when I was younger to try to get into development and got a handle on the old style GML. If it’s the same kind of voodoo, it really won’t help you much learning C++ in Unreal. I’d definitely recommend what another poster suggested - learn Blueprints first, then start small in C++ if and when the time comes that you need to harness it. No better way to learn than by doing.