Yes the final product will preserve the wood grain in some form. The paper has a few images of the final product. They basically boil out all the non-cellulose and compress what remains into a smaller form. I assume the strength is that a super board of the same size would be made of several boards' worth of wood fibers. I haven't read enough yet, but I wonder if this substantially lowers weight / strength. Right now, steel is required for tall buildings because there is an upper limit to how high you can go before wood buckles. There are no 300 m trees after all.
fwiw, I first thought this was going to be some innovation in glue, which allows manufacturers to turn wood chips and sawdust into MDF, OSB, and particle board. These are typically weaker than sawyered beams of the same size because the glue is not as strong as the cellulose fibers that run the length of a beam. (However, they are getting applied more and more in the construction in the US because it is crazy expensive to find a tree that can produce thick enough 40 ft beams, but you can easily get enough sawdust to make an even thicker, precut MDF board.) But I thought no shot, because if you can make glue that is stronger than cellulose, then why bother with the wood?
fwiw, I first thought this was going to be some innovation in glue, which allows manufacturers to turn wood chips and sawdust into MDF, OSB, and particle board. These are typically weaker than sawyered beams of the same size because the glue is not as strong as the cellulose fibers that run the length of a beam. (However, they are getting applied more and more in the construction in the US because it is crazy expensive to find a tree that can produce thick enough 40 ft beams, but you can easily get enough sawdust to make an even thicker, precut MDF board.) But I thought no shot, because if you can make glue that is stronger than cellulose, then why bother with the wood?