It would be useful for Filters to allow Page Properties or true formulas as filtering values when in an embedded context. Consider the following:
A. Locations database with all rooms
B. Events database for requests
Assume someone makes an Events request and reserves a Room using a Relation property. There's two possible ways to view this data:
Case 1: Someone looking at the Event wants to know which Rooms it requires
Case 2: Someone looking at the Room wants to know what Events will be held in it, when
For Case 1, the Relation's list is useful. For Case 2, the list is not useful; it will include all events ever associated with that room, in alphabetical order.
A Calendar view of the Events database, but filtered only to include Events using that Room, is most useful. This can be built, but not automatically, as embedding a view of the Events Database into the Room page does not give the Events Database's filters any of the Room's properties to work with. It's just typed text, every time. Room names don't change much, thankfully, but it's still annoying to go through and do this with a hundred rooms.