does it matter if there is god?

No, not at all

Sure.

If there IS an all-knowing, all-powerful god of the universe who will frequently change the physics of the universe to answer the prayers of the faithful, then it could solve a lot of our problems -- and we could get out of messes by praying.

If there ISN'T an all-knowing, all-powerful god of the universe who frequently changes the physics of the universe to answer the prayers of the faithful, then we need to solve problems on our own and not waste time praying to such a thing that doesn't exist.

All the evidence shows that there's no reason to believe there's any such thing. Prayers do nothing, and no being changes the physics of the universe according to our desires no matter how much faith we have. So the second case is what we're left with -- solving our own problems and not wasting time on praying.

Peace.

Yes, because if God is real then that would mean that there is an ultimate good in the universe that will always deliver proper Justice after death, either rewarding or punishing people depending on there deeds

Depends which god.

Yes - its an important issue. It COULD (small chance) be the answer to why we are here. However we must look at all options.

No.