Is prayer pointless?

I recently responded to an atheist on Facebook:

"I don't understand why prayer is important, especially prayers that are requesting something from God. Isn't God going to do whatever he wants to do anyway?"

No. God acts according to his plan for the world. His plan includes many outcomes which are the consequence of answered prayer. 

"Why, when someone loses a friend or family member to death, do people tell others to pray for them? Does more people praying result in God relieving that person's grief more quickly?"

Merely adding people to the prayer chain doesn't ipso facto up the odds of answered prayer, although it ups the odds that a saintly Christian will prayer for the survivors. 

"Why doesn't God comfort the person at the maximum amount anyway without the prayers?"

For one reason, God has made humans social creatures. Prayer cultivates the virtue of compassion. God often acts through human intermediaries. That's not confined to prayer. 

"Same question with sickness. Why are we encouraged to pray for those who are sick? Doesn't God already know they are sick and that they desire healing?"

i) Another reason is that if we automatically got whatever we need, we'd value it less.

ii) In addition, prayer accentuates our helplessness and dependence on God's mercy. Answered prayer fosters humility and gratitude.

iii) Furthermore, answered prayer is evidence of God's existence, providence, and benevolence. 

"It's like a checklist."

Some people are guilty of mechanical, perfunctory prayers. Jesus warned about that.

"Do these prayers change things?"

i) Some prayers are answered while some prayers go unanswered.

ii) They don't change God's plan, but God's plan includes answered prayer. They change things in the counterfactual sense that certain outcomes wouldn't occur absent prayer.

"Are there tangible results?"

Yes.

"Does God wait for a prayer before he will act?"

In some cases, answered prayer is retroactive inasmuch as a chain of events is already underway, prior to the prayer, which will eventuate in the answer.

Petitionary prayer is the:

i) Perception of a need

ii) Recognition that the need is beyond human ability to secure or ensure

iii) Verbally or mentally articulating that need (spoken or silent prayer)

iv) Directing a request to God to supply the need

Intercessory prayer is petitionary prayer on behalf of another.

Do you imagine that if God exists, believers (or unbelievers?) should never find themselves in a situation where they have need of something, which is even temporarily unmet? Do you think all needs ought to be automatically supplied so that we should never even be in a needy situation in the first place? Do you think we should never have to ask anyone for anything, or just God in particular? If so, why so? Do you think we should never do favors for other people? Do you think we should never be made aware of our dependence on God, assuming God exists?