Starting Chpt 2 Attack on the King that has lost it's right to castle

Here is a chapter that is right out of CT-ART. Most of the combinations involves sacks that drive the king into the center of the board and then skillfully checkmated.

Or as I heard it said on playchess.com:

The King is walked to the center of town in broad daylight and shot.

These are the first three that I am studying:

http://www.chessgames.com/perl/chesscollection?cid=1011660

http://www.chessgames.com/perl/chesscollection?cid=1011660

http://www.chessgames.com/perl/chessgame?gid=1084086

The position above is from the first link. white to move which takes the queen. Why is it we always hear about value of the Bishop pair and never the Knight pair which here is devastating ?