So I know that you should have hard edges across your UV seams on hard surface models for proper normal map baking but I just realised I don't know how this applies to character/organic models. I can't see why you wouldn't but I don't recall ever seeing a character model with hard edges in it.
For a mesh like this, where all the shapes are generally soft and there is enough geometry to represent the harsher angles, there isn't much benefit to setting uv borders as hard edged. There may be some drawbacks to doing it, especially if you need to make LODs. Generally with organic shapes, you'll get more issues with…
Generally that's something you'd do for hard-surface items. It's beneficial when you've got quite sharp edges in the low poly mesh because it means the normal map has less "work" to do - it doesn't have to account for a rapid change in surface normal. Edges with a 90 degrees or sharper can be problematic even for properly…