A Continuously Variable Transmission (CVT) does not make use of gears like a basic automatic transmission. Rather, it uses 2 pulleys linked by a belt. It's a bit like a snowmobile transmission: One pulley connects to the engine, the other one links to the transmission. The belt transfers the power between them.
An automatic transmission uses sensors that allow it to shift gears at the appropriate time by using the internal oil pressure. Shifting gears happens when the transmission is disconnected from the engine temporarily, which is handled by the torque converter.
Both may experience wear, the CVT usually around 100K to 150K whereas the automatic transmission closer to 200K. Repairs for both are costly due to the labor of a transmission removal. A new or a used CVT with low mileage will need to occur versus an automatic transmission rebuild or used component. Thus, increasing part cost for the CVT.