It's sooo Hot out here...
Most of the scoring in DS happens in the last round.... The Domination Cards are crucial to help you prepare for that. They can give you extra action pawns, pull species out of the dead pile, eradicate vast numbers of other species, glaciate your opponent's tile, or reduce the scoring of everyone ahead of you.
...You forgot Leverage against other players if you have the Catastrophe card in your hand...