The problem is, that the Photos on iOS devices (iPhone, iPad, iPod Touch, Apple TV) simply has no support for smart albums at all. Smart albums cannot be created and displayed in Photos for iOS. That is probably why iCloud does not sync them to iOS devices. For the time being create standard albums from your smart albums to see them on iOS devices.
Or use iTunes Photo Sync to sync your albums to your iOS devices and not iCloud Photo Library. iTuens does also sync smart albums.
But you are right - iCloud Photo Library would be much more versatile, if smart albums could be synced to iOS devices and iOS supported smart albums, key words, titles, description, metadata. All is necessary to be able to use and create smart albums. You may want to send feedback to Apple: Photos for iOS - Feedback - Apple