The bottom round flat is a very affordable cut from the Round primal. Like many other cuts in the Round it offers good flavor and is very lean, but can be tough if not cooked low and slow, cut into small pieces, or (if sliced) pinned/jaccarded to break down the dense muscle.
When the flat is cut into (very low cost) steaks, those steaks are typically very thin and either braised or cubed/pinned for improved tenderness.