The hours the starter sits allows the yeast time to work and add flavor.
To add some practical advice,
Sponge grows. Sometimes allot.
I use 2 quart glass bowls.
My white sponge is 10 oz F, 20 oz W, 1 TS yeast, 2 TB sugar, and it usually grows by at least 50%.
My wheat sponge, this last time (I'm still looking for hte RIGHT wheat recipe) I made the wheat sponge with 3 oz Raw Honey, 1 TB light brown sugar, 20 oz Water, 8 oz White Whole Wheat, 6 oz UB-AP, and it crawled out of the bowl (over doubled).
Both are finished with flour to make 32~35 + oz total, proof 1 TB yeast in 2 oz Water with 1 TS sugar, and 1 TB Kosher. No oils or dairy.
For more funk I'll chill the dough 18 ~ 24 hours, for pizza 24 ~ 48 hours. Freezing dough balls and thawing thoroughly in a warm place has it's own joys.
I'm sure I could find a store bought that's similar to these breads.
I too have emulated store bought in so far as to see what was used to make it. I've come to the conclusion just about anything can be put in bread dough.
Wonder Bread. I figure Wonder Breads main function is to keep yellow mustard and bologna from sticking to the sandwich bag.