White chisels are of the best quality, congratulations on your purchase. I have also wondered about the radius one often finds on old edge tools. In theory, I believe the radius will give a slight skew to the edge and aid the user with less effort pushing the slick, also if the back rolls up at the edge, the edge comes out of the cut and is somewhat less prone to digging in. On the other hand, a blunt edge flat back slick will sever grain better with the back right to the surface and a blunt edge will chop to the bottom and corners easier. So, if you are looking to work joints go blunt and for shaping freehand I think the radius is fine.
The reason the radius is there, may not have anything to do with the above. The sides of a chisel tend to wear more at the edge than the center, by my observation. So hand sharpeners wanted an edge first and not a perfect square edge, so over time a radius developed.
Old references, such as Audel's, recommend 15 degrees on a paring chisel and 25 degrees on a framing chisel.