Ans.1. Philosophy is the "science of why" and has churned out Theists and Atheists and everything in between trying to answer it. The question remains. It is "important" because it has diverted our efforts from more productive pursuits.
2. God does not do much of anything. The purpose of all life is to pass DNA on to future generations. If God were real he'd tell you that.
3. Why I was here was adequately answered for me when I held my first born child. I knew at that moment that I had fulfilled my duty as a Human Being and living organism. All questions of "why" fell away for me. I suppose that if it is some kind of personal immortality you seek, that's just not good enough. I stand in awe of Nature and understanding it is one of my favorite hobbys.
01. You are right philosophy is the "science of why" and there are two types of philosophies, one which is aided by the Creator of Universe and another in which people use their own brains and try to figure out their own conclusions.
1A. The Philosophy which is aided by God Almighty is the absolute truth and this is what prophets and messengers of God preach to all people in the world in all ages. This tells them to worship only one God the Creator of Universe and do good deeds and prepare for the last day.
1B. The second path which is based on humans own thinking, is filled with mistakes and errors and no two philosophers agree with each other. They are just like blind people searching in darkness about the path. If they get one bit right, they get 100 bit wrong and no one can tell which is right bit and which is wrong.
02. Again you are wrong about God having NOTHING to do with it. It is the same thing as you knowing very little and boasting that you know all of it. How come DNA got created?
03. If you think you have done your duty as a human "to get your child born" .then what is difference between you and an animal?
Why the powers of thinking and reasoning and choice given to you and not to animals?
Why you behave like animals when your Creator made you above all these animals?
Why not be reasonable and accept that there is a higher purpose of human life on this earth.
If you enjoy nature and it does not bring your mind to who created all these wonderful things, then you do not really enjoy nature, every thing in nature would be laughing at your stupidity!!