Salt Block cooking/grilling

I was wandering around waiting for you wife to finish an errand when I wandered into a Sur La Table store in Boston. I had seen them online and in catalogues but had never been in one of their stores. I was impressed with the scope and quality of what was on offer.

One of the things I stumbled on in the grilling section was a book by Mark Bittman about grilling with Himalayan salt blocks. I had literally never heard of a salt block which at my age is saying something. It looked kind of interesting.... but have any of you tried it? Is there something to it or just another gimmick?

Thanks in advance

It's a big non-poisonous stone. It gets hot if you put it in the oven, kinda like a pizza stone... only very chic.