I think I can safely say that the parts won't be flat to 1000 of an inch (.03mm) - or whatever your tolerance is. However this is something that any existing process can achieve with arbitrary shapes either.

I think this process replaces sand casting, a process that also has many slight deformations. You just make the parts a little big and then machine the important sides to the exact side you need. The downside of sand casting is it often leaves a little bit of sand embedded in the metal which will destroy your tools. If the internal metal quality is as good as sand casting, the ease of doing arbitrary shapes and lack of sand in the metal make it a winner. That you have to have a lathe/milling machine to finish the part is not a change.

If the above is right (it seems reasonable, but I don't know if it is), then beams and and flat stock will continue to be made with existing process. However odd shaped things like an engine blocks it could be a winner.