Answer:
Gatsby's house represents the love he has for Daisy.
Gatsby devalue his possessions according to Daisy's reactions because he wanted to impress her so much to the point that he liked what she likes and would be okay with discarding whatever she doesn't like.
Daisy seems to love the house and everything that Gatsby possess.
Her reaction is important because all of them were done to impress her.
Explanation:
F. Scott Fitzgerald's novel "The Great Gatsby" revolves around the story of Jay Gatsby and his desire to reacquaint and reunite with Daisy Buchanan, his former girl friend. The novel deals with themes of wealth, social class, appearance and reality, love, loyalty, etc.
To Gatsby, all he did, the money, the house, everything was done to impress Daisy. She is everything to him, and his only desire is to be reunited with her. He believes that if he is wealthy, and shows the ideal image of a rich man, Daisy would come back to him.
When he told Nick "I want you and Daisy to come over to my house, [...] to show her around", he wanted to impress her. A few lines later, Nick continues "He hadn't once ceased looking at Daisy and I think he revalued everything in his house according to the measure of response it drew from her well-loved eyes. Sometimes, too, he stared around at his possessions in a dazed way as though in her actual and astounding presence none of it was any longer real." Nick seems to know and understand the real reason for Gatsby to bring Daisy to his house.
In Gatsby's mind, his house seems to be a means to impress Daisy, to show that he's capable of doing all these to show his love for her. And by de-valuing his possessions depending on Daisy's reactions, he wants only what Daisy loves and would be okay with discarding whatever she hates.
As she observes Gatsby's house, Daisy seemed impressed and loved everything, though she also thought it strange that he would live alone in the "gigantic" house.
Daisy's reaction is important for Gatsby because whatever he'd done is all for her. His efforts were to impress her, to try to show that he's capable of being wealthy and he also hopes that she'll come back to him.
