It does a better job of converting sunlight, dirt, and water into something useful.  It's a more efficient plant (heh, like a factory). Hemp is one of the fastest growing plants, and produces excellent fibers we can spin ropes and clothes out of. Since it grows so quickly, and with fewer inputs (soil/air/water), the answer is yes -- it does make those things cheaper to produce, and longer lasting. I'd imagine one can even mix it into concrete!  :)  (We have horse-hair plaster in this house.)