I like your thought process of the man made creating jobs I also like the idea of the rock not being torn from our oceans.
On a personal preference level I like the idea of a 100% pest free rock. Which is what I chose for my tank. Using 25# of dry Pukani from BRS. No unwanted critters, pests nor algaes. I cured it myself using SeaChem Stability for the bacteria. This way I had no die off found with using LR and my cycle time was much faster. It is also much cheaper then LR, a big plus for this reefer on a budget.