I can say from experience that my flag fish eat it, and to the point where I went from alot of it to it being non existent. But Mr. Green is right about their temperament I would be especially cautious with apistos who share a similar niche in the aquarium. This is a very interesting killie that behaves more like a cichlid in breeding habits. But then again apistos can hold their own as well so it might be worth trying it out.
I've had true Siamese Algae Eaters eat BBA but they only get the furry bits and not the "roots" so it just looks like black spots. You'd need to figure out the cause which is usually CO2 fluctuations and too much light or it'll just keep coming back.