I think the point is that some folks prefer blocking out the level from rough shapes first. For BSP would be great, except it’s sort of slow and outdated. BSP tools were updated for UE4 and they are better, true, but I think everybody feels they are still more of a legacy . With that said, road map has “Geometry Editor 2.0” in the backlog, which I hope is a replacement tool for BSP.
The fact that level design changed in past few years from whole level made of bsp to being made mostly of static meshes doesn’t mean some sort of simple modeling tools for blocking isn’t useful. Actually, good and fast (but simple, no one is asking for maya/ in ue) blocking tools can really help in the prototyping phase and also later for prototyping some details (that would be later replaced by static meshes).