Mashing crystal malts improves the extraction, anywhere from 50% to 100% better depending on the Lovibond. Really dark grains, like black patent & roasted barley, the improvement is small.
Remember one unassailable statistic, as explained by the late, great George Carlin: "Just think of how stupid the average person is, and then realize half of them are even stupider!"
"I would like to die on Mars, just not on impact." Elon Musk