I think it boils down to “how much custom merch can we fill it with.” Monsters and HHN past is obvious. So it gets two rooms. Beetlejuice is a headliner with a ton unique, custom merch potential that will sell like crazy. Hill House, though, doesn’t have much that screams “merchandizing,” so fill a Hill House room would be challenging. Eilish merch, regardless of what they try to do with it, would be essentially be concert merch, so a custom Billie room would a bit unnecessary. But a “generic” Attic serves as a catch all for both, plus any other random merch they want to push.