I was making the points that before refrigeration, a lot more salt was used for food storage, and that salt has other major uses besides flavoring food or providing necessary physiological electrolyte. As Ed Conway writes, the production of some important industrial chemicals starts with salt.

I'm also not claiming that legionaries were literally paid in salt. I don't believe that would have been true after the very early Republic at the latest. Probably not after the first kings. The Roman genius for bureaucracy and record-keeping would have sorted out a more efficient payment system quite soon, I believe.