What do you all think about this "Cast Iron Grill Humidifier"?

http://www.surlatable.com/product/661256.do# [1]

The description seems to say that it is just two cast iron boxes with holey lids.  So is it anything? or not anything?

Sometimes in warmer months I will try to bake out on the grill. It is sometimes quite successful, and sometimes not so much. Does anyone believe this might help in baking bread?

I also wonder if this might work in an indoor oven too. I don't like to mess w/ water or ice tossed into a hot oven.

My only concern is that one would be unable to estimate the correct amount of water needed for baking.