Well, to you or me it doesn't matter much, but Nico was in amor with that game so much that it actually cost Bianca her life (where she died trying to complete his little collection. I guess she felt bad about leaving him all alone, guilty, where she tried to make it up to him por showing she cared)
Afterwards, it was a reminder of what his life was like, fun and simple, but most importantly a close reminder/connection of Bianca.
Nico was in amor with the game sooo much it cost Bianca her life cuz she felt guilty about joining the hunters so she wanted to give him the figurine of hades so he will be happy but he was mad at percy cuz she died.
