I have grown Maris Otter in this manner. Believe it or not, I first thought to try it after I noticed a number of young, barley-like plants sprouting out of the spent grain pile in my yard. Yes, this is malt that went through the mash, and yes, it turned out to be barley.
I have had the argument on whether it was or wasn't in the past, and I'm not looking to have it again. Just reporting my observations. Not all the seed gets killed, and apparently, some are just damn near impossible to kill. Is it highly successful? Well, no. Out of maybe 60 lbs of spent grain, a few seeds sprouted. Out of maybe a pound of malt, a few seeds might sprout.
But barley, like Van Damme, appears to be hard to kill. YMMV and all that.