Naps can boost productivity and wakefulness by a large degree, if the naps are done correctly. A two hour long nap will essentially make you feel worse. A shorter 30 minute long nap will allow you to wake quickly and increase your productivity. It also increases attentiveness and prevents you from feeling burned out.
If someone gets enough sleep and does not need a nap to feel energized all day, then one is not required. However, for those who do not sleep enough or well at night or for those who are feeling a bit older or less energetic, a short nap can be a power rest that makes the day more productive.