Although the quality of being self-satisfied is eternally present in Krishna, the quality of enjoying pastimes is also eternally present in him. For the Supreme Lord to possess contradictory characteristics in perfect harmony is natural. In one aspect, Krishna has the quality of self-satisfaction and in another aspect, he manifests his opposite quality of enjoying pastimes with others.
The impersonal Brahman is Lord Krishna's bodily effulgence. As fireflies seem brilliant when the sun does not shine, so the impersonal Brahman is glorious only when Lord Krishna's form remains unseen.
Those who believe God to be impersonal simply identify Him with some power or attribute in nature, though in fact He is above nature, her laws and rules. His holy wish is law and it would be sacrilege to confine His unlimited excellence by identifying Him with such attributes as omnipotence, omnipresence and omniscience. His excellence consists in having in Him mutually contradicting powers and attributes ruled by His Supernatural Self.