/jp/ - Otaku Culture

Could I get some assistance please? I can't make sense of that 「に入れるのに」 on the first sentence and it's making me lose confidence on what I think the second one tries to tell me.
From the second one the 「に入るもの」 is just "the (best) thing that goes into the star" right? But what is different in the first sentence? Wouldn't it be just 「( )に入れる最もよいものを、」if it followed the same logic? What's the のに doing there?