The universe, as we know, has existed for approximately 14 billion years. Many speculate that there wasn't literally "nothing" before the Big Bang. That, in one way or another, the universe has always existed in some form; and will continue to exist in some form or another. Basically, the universe really has no real starting point and is "eternal"; even if it does go through cycles of creation and destruction.
With that in mind, if the universe doesn't necessarily need a singular starting point, then why does God? Why is it more plausible to believe in an eternal universe rather than in an eternal Source? Why does God need a creator?
Usually the argument of god needing a creator is a reactionary one, and is most meaningful in the context that it is usually made.
It's usually made in response to the idea that the universe requires a creator. Some people argue that the universe is too complex or too specific to have always existed or to have come from nothing, and so, they argue that a creator is required for the creation. A watchmaker for the watch, in other words, because something as complex as a watch doesn't just appear out of nowhere.
But then the counterargument is that if someone argues that the universe can't come from nothing and can't have always existed, then how can it be the case that some being capable of creating universes, has either always existed or has come from nothing? If a watch is too complex to have always existed or to have come from nothing, then how can a watchmaker have always existed or come from nothing? Basically, adding a creator for existence doesn't solve any logical problems associated with its origins; it just adds another layer, adds more complexity, without answering anything.
So it's not that the universe requires no creator but a god does, but rather, if the idea of a god needs no creator, than the same logic applies to the universe not needing a creator, unless someone can provide a coherent reason as to why one set of logic applies to one but not the other.