We bakers use words like "proof." It's silly. There's nothing to prove. What it means is, "fermented." Here's the thing, the yeast is going full blazes, and if it was baked at its peak its flavor would be underdeveloped. Therefore, the dough (actually near-dough) is chilled to retard the yeast's progress. The element of time allows bacteria, enzymes, and a variety of other organic chemical reactions to occur which impart flavor, tang, and improvement in texture that quick breads utterly lack. If it were not chilled, the yeast organisms would consume the sugars derived from the starch in the flour and the whole matrix would collapse. The collapsed structure is unsalvageable, although it can be fed more flour in bulk to form an entirely new matrix. Commercial yeast can be over-proofed, punched down, then re-risen because the gas production is so much greater relative to starch to sugar consumption. In other words, the isolated yeast organism selected for commercial dry yeast is particularly gassy. Using wild yeasts, the sponge (the proto-dough matrix) can be stretched, as it is here, to redistribute the yeast cells, and gently patted to force new yeast to yeast contacts, after its initial peak, and rise again to a new peak, but only until the sugars from starch is consumed. After that, nada.