In my neck of the woods, unground salt is much, much cheaper than ground. Ground salt can basically be only found coming in a plastic dispenser. It could be argued that throwing all these plastic containers away isn't great for the environment.

I only realize that I've never thought of comparing, but I've got the habit of using unground salt when cooking. My grandmother used to do this for some reason, so I picked it up.

Unground salt is also useful for cleaning things, like cooking pans.

It's therefore easier to only buy salt in one big pack that lasts forever.