I have tried the aforementioned recipe subbing beer for water as well. I tried it with stout, but it didn't have the stout character I hoped for. I tried it with a hoppy beer and it was unpleasantly bitter.
Can't remember where I read or heard it, but beer yeast is best suited for a slow rise dough, hence the dutch oven recipe. But I have had success reusing beer yeast for pizza dough.
I tried an IPA once and it was bitter. I thought it would be good with chicken soup (richness and fat to counter the bitterness) but yeah, by itself it wasn't great. Berliner weisse makes great bread.
I've never heard that about beer yeast, but slow rise dough is great. Many of the enzymatic reactions that happen in the dough overnight are the same as those in a mash.