The Lord heard the story of Sākṣi-gopāla with great pleasure because He wanted to impress upon the atheists that the worshipable Deities in the temples approved by the great ācāryas are not idols, as alleged by men with a poor fund of knowledge. The Deity in the temple is the arcā incarnation of the Personality of Godhead, and thus the Deity is identical with the Lord in all respects.