Using numerical methods for secret codes provides massive advantages over simple letter swapping. Turning text into numbers unlocks the power of mathematics, making codes significantly harder to break. A single mathematical operation can change an entire block of text, erasing recognizable language patterns. Mathematical equations can scale to any complexity level, unlike a fixed 26-letter alphabet. Numerical code has native compatibility with machines, computers do not understand letters; they process information using binary code. Representing data numerically allows mechanical rotors (like the Enigma machine) and microprocessors to encrypt data at lightning speeds.