The Prius uses a Power Split
The Prius uses a Power Split Device transmission, not a belt-and-pulley CVT.
The Power Split Device is a simple planetary gearset. The center sun gear is driven by the MG1 electric motor. The planet gears is driven by the ICE (through the gear carrier), and the outer ring gear is driven by the large MG2 electric traction motor. This setup has no belts, no clutches, no torque converter, no gear-shifting wear-and-tear. That is why the transmission fluid in the Prius does not require changing.
The center sun gear MG1 is a 25hp electric motor. It is used to crank the ICE. That is why the Prius has no traditional starter motor.
And regen braking using the large MG2 traction motor for the Prius slows the car down to 7mph before the disc brakes take over. That is why the disc brake pads will last past 150,000 miles. Not a typo.
The Prius Hybrid Synergy Drive actually makes the car mechanically simpler than a normal car. It is the control electronics that is complicated. That is why the Prius needs so much less maintenance than the Fiesta, and one of the reasons why its cost of ownership is actually LOWER than a Fiesta.