Why is the direction of travel more or less interesting than any other galactic coordinate system, when looking at the Earth from space? I can easily imagine us

Why is the direction of travel more or less interesting than any other galactic coordinate system, when looking at the Earth from space? I can easily imagine using the center of the Milky Way as my reference point. Why do you think the Earth moves like Superman, head-first into the void? Couldn't it be falling through space, bottom-first?