She wouldn't need to ask you if she believed you knew everything running in her mind. Since you don't, and since she doesn't believe so either, she has to ask you. If she truly believed you knew everything running in her mind as well as she did, then neither of you would find any purpose or meaning in asking. Because the need is invalidated by omniscience. Do you ask your heart to beat at X Hz when you are performing a strenuous activity? No. Would you enjoy asking your heart to beat faster, even though you believe your heart knows what it has to do better than you do? You wouldn't, unless you were insane (compare this with the previous comment of mine, the part about the pertaining activity being nonsensical).
Second, as in the quote above, prayer is not only petition, but communication--or, to be more accurate, communion. My daughter not only talks to me; she talks with me, a two-way communication, not only for the purpose of sharing information, but for the greater purpose of sharing relationship. The most important aspect of prayer is not what we say to God, but what God says to us: God already knows our needs, but we do not know the extent of God's nature or God's will, and the more we can experience that communion, the stronger our relationship to God.
Your faith in your god to know your heart in and out, your intents and feelings, renders unnecessary the need for this mental / verbal / physical communication because by the repercussions of your faith, you ought to be 'spiritually' connected, and believe that you are so, whose lines of communication are superior to anything you do as a substitutionary activity to pretend to give a physical aspect to this 'communication'. Since a believer believes this to be the case, the unnecessary and self-contradictory nature of prayer becomes self-evident. To put it in simpler words, does the faith of a believer weaken when the believer falls into a coma? What about when the believer is in subconscious states, such as during deep sleep? If the answer is no to either, then my point remains validated.
At best, you can plead for a deistic god with your arguments, no more. The type that does 1 Samuel 15:3 is totally repulsive to me. Add to that, the prayer fluff, and the falsehood becomes unavoidably evident. Do you find this verse difficult to accept, even if you eventually do?
Oh, and I enjoy my weekends. My weekdays, too. After all, we live only once, and eternity is a fantasy. About half of all natural conceptions end up in spontaneous abortions where the mother isn't even aware of it, usually. Such is the nature of life.
So it is your own private intuition which rules.
Tell me then, since all sentiment and moral values are usually held by atheists to be epiphenomena, a swirling of cerebral biochemistry in response to cultural trends, coupled with instinct -- and sifted by the imperfect, impersonal sieve of survival value over time and populations --
since death comes to everyone anyway, and natural selection operates without pity to kill individuals and populations alike --
where's your beef?
Cheers!