It's more of a way to get rid of BMC without actually drinking it.
I did a darker beer once and didn't retard, I thought I was getting a slight bitterness to the dough. I'll also use my cloudy pulls from my homebrew (1st pint/last pint) to make the dough. I usually don't notice any flavors coming through because I almost always make the dough a day ahead - and I think the fermentation/retarding process scrubs the subtle flavors out.
Have yet to try "Pizza Beer" as an ingredient. The guy who makes it says the flavors come through if you use the dough right away, but will fade if you retard overnight. So if you use fresh dough, you could probably add bitterness or maltiness to the dough to compliment your ingredients depending on your beer selection. I've been using this one for years - stretches easy, crisps up nice. Honestly that's all probably due to the butter. The flour is from Costco in 25 lb sacks - it's got some barley in it. I think that may have some affect on the crust crispness factor a bit too.
This comes from a Zojirushi Breadmaker manual. I'm not claiming it as my own, only that it's my favorite for over 4 years now.