Action rpg

please address this
i would also like to know what i should not use blueprint for.

i have watched many tutorials and they all use blueprint for attacks (including registering damage) but this sample uses cpp to register damage.
also from the documentation, inventory is using AssetManager? which is cpp.

other things i know about that we have to use cpp for is
Nigeria and GAS only supports CPP but what is the difference between using GAS and making stats a variable in BP which most tutorials do?
also AI is one i found to be frustrating to make when using BP to create and you guys have said multiple times to use cpp if there is a need for complex AI

also off topic but can you show some settings we can turn off in UE so that we can make our stuff with a lower end PC?