Describe what you mean

....you can buy salt slabs that you preheat and use to cook things at the table....and there are blocks of salt meant to be crushed and sprinkled on your food.
Which do you mean...I have used both.

We just purchased one for our daughter for her birthday a few weeks ago. It is a fun, different way to cook a meal. You do have to cure the block first. Place the block in a cold oven. Turn it up to 180 degrees. When it reaches 180 degrees remove it and wait 30 minutes or so. You then put it back into the oven, turn the temperature up to 400 degrees. white bumps or bubbles may form. Just wipe them away, it is only the moisture boiling out of the block. You can now cook on your salt block. Heat at 400 degrees for 30 minutes, remove the salt block to a heat resistant surface. Toss your thinly sliced meat or seafood lightly in seasoned oil. Do Not Add Salt! Put them directly on the salt block and cook to desired doneness. For cleaning, just wipe with a damp towel or sponge. Do not soak or put under running water. dry thoroughly.

Is there any practical reason to use a salt block? It seems like a fairly convoluted and messy way to cook, with no clear advantages.

Practical??
The presentation is lovely....and no added fat is needed, the food is naturally and lightly dressed with a mineral rich natural salt.
Are these "practical"r easons?

I guess I'll just have to try it! :)