You are right. We should only use that for images that have no transcribable value. Might be a good photo of legs/arms/trees/streets/etc, or a blurry mess.
However, too many times I have seen where someone tagged it bad photo when it was the best anyone could have done in photographing an old stone. Sometimes there are clues which allow me to figure out what is on the stone, and I can compare it with data from other sources (FAG, Ancestry, local cem records).
Thanks for your prolific work.