Formless and Empty
The first we "see" of the earth we find a vast wasteland. There is no reason to think of the surface of a desert, though.
If we take these verses chronologically, the first phrase describes the earth before it takes any form at all. The basic meaning of תֹ֨הוּ֙ (tohu) is "laying in waste", that is "worthless". As tiny particles without restraint, the quarks and electrons were in complete chaos.
Paired with tohu is its rhyming twin, bohu, which means "empty". The former is used by itself many times to indicate insignicant and even worthless things. The latter term always appears with it, denoting emptiness.
Together, the description is of something powerless on its own. After the particles acquire the practically unbreakable "strong force" God would have a stable base upon which to build.