People get mixed up with thinking hardcoe is an difficulty it is not all it is is adding relism to game like above said the naming is bad.
Well, some of it is definitely supposed to increase difficulty. For example, the stimpacks only healing over time, and crippled limbs being harder to cure. I've found that those two things definitely make combat a little more tactical. But as for food, water, and sleep... it's fairly easy to keep those up, especially since most of the water in NV is pure, unlike FO3's irradiated water.