Ground into flour can usually lead to stuck sparges. And for BIAB you may have a greater amount of particles flowing through your bag into your fermentor. I'm not sure what the impact will be (certainly more Trub), but maybe it will affect the flavor.
It'll make the beer haze up by fridge time in my experience. Seems to put more dissolved protiens in the beer. They'll settle out clear in the bottles,& haze up bad at fridge time. So I started using super moss as of the last batch to combat the haze. & got the barley crusher grain mill to get a better crush that's not so fine.