My conjecture: salt grinders create more irregular shapes than provided by commercially made table salt. Irregular shapes mean more surface area, which means faster absorption into the body, which means tastier food.
I'm a big fan of tomatoes, and one of my favorite dishes is sliced tomatoes, salted, and eaten with cheese.
For some reason, normal salt just sticks on the top of the tomato despite it being wet and I can "taste" the salt not just saltiness. However, with crunched salt crystals, they basically dissolve and disappear into the moisture of the tomato. This just tastes better too.
Don't ask me why or how it all happens, it's just what I've found using my taste buds.
Probably the anti-caking agents in the normal salt absorb some of the wetness and have it stay clumped up instead of diffusing through the tomato liquid
Totally without evidence.