For example, if the "number of plays" counter have been increased when a movie is in a playlist the movie would not show up in the smart list.
Unfortunately, we can't do this at this time.
Or you could create a totally separate user defined field to accomplish the same thing.
For me, this is the path of least resistance... I've just added it to our "Recent" movies view and it's pretty quick and simple...
Our recent movies view uses the following rule, and no categories....
([Date Imported]=<7d or [Number Plays]=[]) ~sort=[Date Imported]-d
So, it only lists movies imported in the last seven days,
or, movies that haven't been watched yet. Watch one of those, and, if it was imported more than seven days ago, it drops off the list right away, and if not, it drops off after the seven days pass.
Create a new field called "Watch Later". I set mine for just Video and TV, string type, standard edit.
In "Options > Theater View > Advanced > Tag menu fields (Video)" add this "Watch Later" field to bring it to the top of the Theater View tag menu list.
Update the "Recent" view "files to show" rule as per below...
([Date Imported]=<7d or [Number Plays]=[] or -[watch later=[]) ~sort=[Date Imported]-d
When you come across one you want to watch again later, flit across to the tag menu and enter anything in there... "a" is quickest and easiest.
This will now be included in the "Recent" list, and appears immediately.
To remove it from this list, go back to the tag menu, hit "Clear" then "Save" and it is removed from the "Recent" list.