PFR, tofu is nourishing and clay is not. Also, you can actually chew tofu. Try that with clay and your teeth will suffer.
Tofu don't get no respect. The stuff is bung-full of protein but it has no character, good or bad, so the cook is responsible for giving it some. Dependence on processed beans (such as tofu) is the reason behind the amazing flavours Asian cuisines are noted for.
In my youth, I read French cookbooks as if they were novels, and did my best to make everything that fit into my scanty budget. I remember making, eating, and actually enjoying a tripe dish involving lots of onions and, oddly, prunes; it was rich and strange. But then I signed up for a history course (being a student at the time) and soon found myself reading "The Road to Wigan Pier" by George Orwell. It includes an unpleasantly vivid extended discussion of life in a working-class boarding house circa 1935 that put me off my feed for a week, and permanently relieved me of any desire to eat tripe ever again.