Have the ability to establish a web gallery linked to a smart collection. Then when you add photos to the smart collection and subsequently click on the web module the smart collection's web gallery is automatically updated to include the photos just added.
Smart collections are actually permanent, Always On and searching, Filters. You the user don't really Add images to Smart Collections. They get added automatically by the search criteria you have specified in the smart collection. Because of that they aren't really looked at as standard Collections. If you have smart collections now that you would like to sync up you can select it, select all the images in it and then place those images into a standard collection that can be synced with the web/mobile system.
If after you import more images that fit the criteria for that smart collection and you select that smart collection you will see which images are and which are not synced with the web/mobile system by the Sync Icon, or the lack there of. You can then place those that are not synced into the standard collection that is synced.