Why deity worship is essential and not optional?

Devotee (1): Srila Prabhupada, if Krishna is everywhere, why do we stress the importance of living a very strict life in the temple atmosphere?

Prabhupada: But have you got the eyes to see Krishna everywhere?

Devotee (1): No, Srila Prabhupada.

Prabhupada: Then you must attention give to temple. When you have got the eyes to see Krishna everywhere, you may not require temple worship.But why do you try to imitate that? You have no eyes to see that. Yes.