Why use a CFG instead of a DFG

Question

I just realized a Control-Flow Graph (CFG) is composed of basic blocks, which is a set of instructions. It is mentioned that you can still do stuff like dead code elimination and whatnot, with the CFG, but that seems like you'd be reaching into the basic block to figure that out. At that point you are dealing with individual instructions. But that's the domain of Data-Flow Graphs (DFG). Data-Flow Graphs are made of connections between individual instructions.

My question is, why not just always deal with individual instructions instead of the basic blocks. It seems like in the end you are using individual instructions anyways. Wondering the advantages a CFG has over a DFG, and vice versa.