That is true, and we dont make that distinction in swedish but I have found, even though I have very limited experience, that it seems to be significant differences chopping evergreens compared to deciduous trees regardless of "hardness". One example being that when chopping softwoods much greater care needs to be taken to avoid knots but hardwoods tend to have much less uniform punkiness (when speaking of dead wood) making it harder to predict.
Regarding the sharpness of the bit, one thing I dont understand about the argument that the reason Gransfors and Wetterlings axes have very flat cheeks is because they are designed for Swedish trees, is that we have mostly spruce, pine and birch. On all of which I would prefer a really pronounced convex to avoid sticking. Getting enough penetration is not really a priority.