If you want your edges to be smoother, make em smoother in the high poly phase. This is an art direction, maybe tech art decision to be made early on and then everyone can follow this ruleset for consistent bakes/textures.
I don't use hi poly mesh for such things at all. All the edge rounding could be baked by just using rounded corner / bevel shader or whatever your 3dpackage or renderer call it and this tiny "detail" could be just painted in substance painter, 3dcoat , or any texture soft. It's a bit less easy on cylinders crossing each…
I missread the OP. :# I think he meant inflating low poly. It's what I meant. Doing it to Hipoly is indeed weird. Inflating low poly along vertex normals to bake world space normal map on the other hand is where low poly itself become the cage . That way it works in many renderers that are not supported by regular texture…