Well, to me, I see the emotional impact seeing the den renovated on Barry. Even seeing the steps completed and the living room, Maureen got emotional. I think, seeing the sound stage being "remade" into real life living spaces, where they spent five years together, brought back those memories, and then knowing that Florence, Bob, and Ann aren't there to see it too. And with the upcoming episodes, there was one where (spoiler tagging just in case)
I admit, I am cynical about most things these days, but when it comes to these people and cast? My inner child refuses to believe that they're not emotionally invested in seeing "their" house come to life.