Do note that you also have a much more
mundane Left Shift in your first pic -
it still works fine even though no
binding was created in the Input
Bindings, right?
Yes, the shift does work without any input mapping. Which confused me even more 
I was just about to ask “why?”, when I realized… read below
Nothing stops you from doing this in
the Player Character (or use the axis
equivalents which I’ve shown in the
pic earlier on.):
Thats a great tip! Thank you.
If I intend to have the character behave and mapped in an certain way, this would render the whole input thing unnecessary, right?
The final check to see if I got it all right:
You answered “Yes” to the question “the Blueprint should be able to let me move around despite nothing is set under Project Setting > Input?”
If you referred to the usage of axis-equivalent nodes, then aight, got you. If however you meant that it should work with the InputAction nodes as in my screen capture, then it doesnt work for me. And therefore: why and what should I do to make it work?
I need to make sure if 1) either the blueprint with InputAxis nodes can work by themselves or 2) if blueprints can auto-generate input mappings under Project Settings.