Cable machines are different from Smith machines because they create adjustable cable resistance, while Smith machines guide a bar along fixed rails. A cable machine lets the user pull from different heights, angles, and body positions. A Smith machine is built around a guided bar path for squats, presses, rows, and similar loaded movements.
The practical choice depends on movement freedom versus guided bar support. Cable machines are better for rows, pulldowns, rotations, curls, pressdowns, and accessory work from multiple angles. Smith machines are better when the user wants a fixed bar path, easier setup for barbell-style lifts, and more structure than free weights.