Much is said about the days of Genesis 1; much of this muchness is about explaining that they aren't days as we know them. But this presents massive theological problems, which seem to be put to one side.
If you make the days figurative you dehistoricize the creation, removing it from our time-line, and you depersonalize it, removing God from our world.
In denying the creation account really happened, you mean that something else happened, and it is this something else that defines and expresses what is truly real and denominates every aspect of our being and nature. Whence the information about this 'something else'?
The days connect God to us: they show the tempo of creation is the same as our life tempo...the first move of fellowship between creator and creature. God thus shows himself present and active in the same world and by using the same basic denomination of existence that we are in. The world created as the setting for that fellowship.
The days ground our relationship with God, our understanding of ourselves and the point of salvation in Christ.
The days are there for a reason!
Because the days historicise time: give it tempo and dimension, they show the dynamic conjunction of God's domain and our domain. That God, the one who is love, not only 'is' but is here with us. Genesis 3:8 exemplifies. The God who is near, not far of, and with connection defined in terms of the shared tempo of passing time.
The days thus show 'heaven and earth, creator and creature, come together' in the same flow of time and material realm that circumscribes our living. Yet at the same time they show that God creator is distinct from, prior to and sovereign over the creation he has authored.