The purpose of ‘Birkas Hamozon’ is to draw down blessing into the one who is Bentching’s portion of this world. This is because even the Mitzvos become enclothed within material objects such as woollen Tzitzis and leather and parchment for Tefilin.
So, most certainly one of the objectives of ‘Birkas Hamozon’ over physical food items is to draw down blessing into [the] physical objects such as ‘land’ and ‘food’.