One of the most iconic checkmate with many ways to do it. The queen and rook can do a back rank checkmate, you can also sacrifice your queen or rook to back rank checkmate. For example queen check e8 rook takes queen rook takes rook and checkmate
I guess he learnt he could chackmate in this amazing new way and wanted to share his skills with the world. “Queen check e8 rook takes Queen rook takes rook and checkmate”.