Ge on/off switch vs add on switch

hello

What’s the difference between the add on switch and the not add on one? There is a huge difference in price tag. Can i get away with using the cheaper one if i already have the ge bulbs?

The “add-on” is just an auxiliary for the primary switch. It won’t work by itself and MUST be used with a GE/Jasco on/off or dimmer switch. (It’s for 3-way switches)