What are the advantages of napping?
Napping doesn't replenish energy as well as sleeping in a bed. --The Sims Wiki
Why would I ever want my Sims to nap instead of sleep? Was this added for realism or does it have any actual use?
(in The Sims4) Completing a nap provides a 6 hour Energized moodlet, which is one of the longer moodlets available.