Wrong. Think about it...sodium is an electrolyte. In fact, it's the most important electrolyte (and the major constituent of sweat).
Some people need more, some need less (sweat rates and the sodium content of sweat vary by individual, and with training and heat acclimation). But if your rides are hot, hilly, or hard you need sodium. Otherwise, you risk
hyponatremia.
But my home made gel has salt in it. Should that not be enough?