@Boney assuming no living thing passes through the entrance how
long does it take the entrance of a liminal realm to close?
Just being up front here since I know you dislike leading questions for some unmentioned idea, I am trying to find a use case for liminal realms and it occurred to me that while a bolthole is not as good as a Bag of Holding for looting purposes as long as you can close it in good time it might serve decently well. Taking for instance our looting of necro-Hogwarts the problem with just coming back for the rest of the stuff was that the peasants of the nearby settlement would loot the place long before that could happen, but if we could have stashed the stuff in a liminal realm, even briefly in a place random peasants cannot find that would have solved the problem. It's not like it would have been very likely one of them was a daemonologist.
This is not a perfect solution mind it would not have helped for Kurgan looting, indeed any looting where we cannot come back for more, still if it could be done that would be one use.