In a recent article I read that seeks to rebut the views of Hugh Ross and other 'old earth' 'creationists', much time was spent, as is usual, on textual issues, without touching the important theology.
Ross et al skip over an important theological implication of the sequence of ordinary days in the Genesis 1 account. It has a general timing implication, of course, and that timing teaches us about the order, dependencies and nature of causality in the creation (that is, being directly connected to the word of God).
It also has an important implication for the relationship of God and man.
It characterizes the immanence of God and shows that God is active and present in the 'life-world' that we are constrained by: he is God 'here and now' in the world and showing this by creating in the terms of the world that we know and are bound by.
His work is timed as is our life, and in the only tempo that is unmistakable across history and cultures: day by day. It uses the categories, constraints and historical flow of our world: driving the point that it is done in the very same world that we live in. The world of creation and the world of our lives as its stewards are the same world. This is the unmistakable thrust of the passage. It shows movingly that God's domain overlaps with ours: heaven and earth shown in spiritual connection. He demonstrates that he is with us and proximate, not remote and inaccessible. Note, God shows this, he doesn't merely assert it, but gives the grounding reality that establishes this (I am thus reminded of Chekhov: "Don’t tell me the moon is shining; show me the glint of light on broken glass."). This is echoed in Genesis 3:8, but with great sadness here as A&E hide from God and repudiate relationship with him.
All in all the Genesis 'days' show the creation within the flow of biblical history and the continuity of God's word, action in creation and our experience of that creation as the 'creatures in his image' in a continuous isotropic fabric. Creation is in the time and space that we are in. It is continuous with our world-experience, and God's presence is thus continuous with the same biblical history that connects us to the seed of Genesis 2 and his redemption. We are thus demonstrated to be part of the continuous ontology of God's creation, and the continuity of our genesis and the history of the 'seed' of Eve is intermingled from the very start, and reprised in the genealogies replete in the Biblical collection.
Denying the direct information in Genesis 1 places the creation in another time and space from ours, it inserts a disjunct in biblical history, severing us from this astonishing and gripping intimacy between God and man-in-his-image, mythologising it, deracinating it and disempowering it, and all to save materialism!