There's no obvious reason to assume that the very same rare properties that allow for our existence would also provide the best overall setting to make discoveries about the world around us. We don't think this is merely coincidental. It cries out for another explanation, an explanation that... points to purpose and intelligent design in the cosmos.
What would happen if the moon were not there? Then our tilt could swing wildly over a large range, resulting in major temperature swings. If our tilt were more like ninety degrees, the north pole would be exposed to the sun for six months, while the south pole would be in darkness, then vice-versa. Instead, it varies by only about one and a half degrees - just a tiny variation, because the gravity from the moon's orbit keeps it stabilized.