Not a necessity but by all means useful. You eat protein in various forms as it is now, the only thing a shake will do is increase the amount you have in your system. Protein being essential for muscle repair and building means that (to a limit) the more you have the better. Will it make you fat around your belly - not necessarily, but drink shakes and not train at your peril, the excess calories from shakes will make you put on weight, not the protein itself.
Shakes aren't cheating, no such thing.