Once you recognize the God in your inner-self, after that, why and how can one see God in an idol?
That is not required. We do it to preserve the tradition for future generations. When we offer flowers and go around the idols in temples, it is to preserve the rituals. God is all permeating, he is there everywhere. Most importantly God is present in you. You can experience it during meditation.
It is not that these rituals don't have an effect, energy is definitely there. If you sit and meditate in the same place every day, and someone else comes and sits there, he can feel the difference. How many of you feel that once you step into the ashram, you start feeling good vibrations? (Many in the audience raise their hands). This is because many people meditate here together. Similarly, when in a temple, an idol is established and when people worship together and offer prayers, then those vibrations are created.