Regardless of the reason pool houses may have been built, they still serve a purpose. A pool house can be a hideaway, a sort of outdoor office (with a roof and walls), a clubhouse and sleepover room for tweens -- whatever you desire.
Pool houses are also attractive ways of harboring pool and spa equipment, which is often an unsightly elephant in the backyard.
If you plan to build a pool house in your backyard, check into your city's zoning requirements, whether it's a prefab storage shed you ordered online or a little dream house with a guest room, wet bar and spa.
While gazebos and cabanas usually aren't built with bathrooms, showers, or private changing areas, they can serve the same purpose as a pool house for a lot less cost.