We're also described as under a solid sky, not within a solid shell.
Earth's creation is described as spreading earth over the top of The Waters Below, like a mud pie, not balled up as a sphere....
A related thing is this verse involving a "tent":
Isaiah 40:22
He sits enthroned above the circle of the earth, and its people are like grasshoppers. He stretches out the heavens like a canopy, and spreads them out like a tent to live in.
If the earth is a ball, the throne would only be "above" some of the earth - to some people the throne would be to the side, and to others it would be below them. If they were grasshoppers on a flat earth, God would be able to see them, but on a ball some would be hidden by the earth. A tent could exist above a flat earth, but not really around a ball.