Theists offer the God hypothesis as an explanation for the most fundamental questions about this universe. They consider it a beautiful, complete explanation for everything. The major problem with it is that it doesn't actually explain anything at all. It simply shifts the exact same questions one step further, with the drawback that one additional mystery is added in between.
Theists also want God to be exempt from the very problems that it's trying to solve.
Why does the universe exist? They say that it's because of God. Well, why does God exist? There is no answer to this. He just does, period. God's existence is exempt from being explained.
How did the universe come into existence? They say that God created it. How did God create it? Again, no answer. It's just "somehow." No further explanations are needed. Thus this "explanation" doesn't actually explain anything.
What is the cause for the existence of the universe? They say that the cause is God. Well, then what is the cause for God's existence? But no, God is exempt and doesn't need a cause. Again, a mystery is simply replaced with another mystery.
They say that the universe cannot be infinite because it's "logically" impossible (as if logic had anything to do with that.) Yet they claim that God is infinite and has always existed. Again, God is exempt from these rules, with no justification of any kind. He just is, period, no justification or demonstration needed.
The fact is, the "God hypothesis" is completely useless. It actually doesn't explain anything. Moreover, it's worse than no hypothesis at all because it only adds more questions than it answers.