I don't think you realize just how much salt that's going to be. Plus the brine they get afterwards isn't just pure salt. It has contaminates including sea life. So there's a lot more process to making usable salt.

Also, these seem generally cheap to produce so the chances of smaller cities and vilages to obtain one is pretty high. So even if salt was able to easily able to be gathered from this process, there's going to be a lot of excess salt lying around.

Desalination seems great on the surface, but until we have a solution for brine it's going to be another technology that will only hurt us in the long run.