Sure you can put those edges on separate layers, too (although it's typically not a very good idea to put elements of a certain group hierarchy onto different layers because if you are a messy person like me, you can easily end up confused).
The reason for an ultimate hide for these edges is generally that you are really unlikely to need them (especially with nicely modelled foliage where image files of leaves and such are much more spectacular without edges). Even from a medium distance those condensed edges are very ugly looking.
BTW the same "tip" goes for 3D Text. Make something and watch it from a certain distance without hiding the edges. It will soon become illegible.