"Consider to sync your library to the iOS devices with iTunes Photo Sync. This will sync the smart albums as well.
But iTunes Photos sync is not available, if the iOS devices are using iCloud Photo Library."
His first statement was "Using iCloud Photo Library on all my devices."
And switching to iCloud Photo Library "took away" the ability to sync smart albums and faces albums. That is why I suggested to go back to the better syncing method that does what Dennis wants to do and drop iCloud Photo Library for syncing with iOS devices. iCloud Photo Library is very versatile for syncing Macs - then smart albums do sync, but on my iPad I pretty soon stopped using iCloud Photo Library. It was a pain. No smart albums, and I was forced to enable "Optimize", because the iPad has only 64GB storage. So most of the photos needed to be optimized and when I want to see them I have to watch the loading indicator for a long time until the photo finally appears. My library is too large to sync it to the iPad with iCloud Photo Library. Syncing the photos with iTunes to the iPad is so much simpler. Plug it into a USB port, select the albums and smart albums I want, and I will have have my photos available at the full resolution without needing access to a network.
IMHO it's absolutely ludicrous to take away this syncing feature (IIRC it was available on iPhoto). Those of us with tens of thousands of Photos depend on Smart Albums (and Keywords) to organize our photos.
iPhoto does not support iCloud Photo Library. It can sync smart albums with iTunes, and Photos can that too. iCloud Photo Library is not compulsory.
And yes, I've sent plenty of feedback already to Apple. Smart albums are an essential part of a photo library. Photos iOS on the iPad and iPhone is just too limited. It does not show most of the meta data, it does not allow to to add titles, captions, keyword or to tag photos in any way other than marking them a favorites. And without the ability to see or to add metadata it is not surprising that we cannot create smart albums that need meta data. Photos on iOS looks like Photos on the Mac, but is a poor relative.
To be able to sync the libraries properly to iOS device Photos on iOS needs to be vastly improved, at least to the level we previously had with iPhoto iOS.