Shaping baguettes using three folds vs. rolling it up? What's the idea behind the standard French technique of three folds to shape a baguette where you fold it in from top and bottom and then the whole thing over, sealing it with the heel of the hand? The standard Mexican and Vietnamese method is to simply roll the dough up and seems to work just as well for making bolillos or banh mi. I have also seen artisan bakers using the roll-up method to shape batards and probably baguettes as well. Which makes me wonder, if the roll-up method works just fine, why did the French come up with this 3-fold method? What advantage could it have, theoretical or practical?
One of the key skills in dough making is forming a decent crumb and light texture. While the action of the yeast will go a long way to doing this, by folding the dough in such a way, more air is trapped within the pocket. It is the same way when making pizza, you should not press on the outer crust (or use a roller) on the pie itself, as this expels air or CO2 and could lead to a heavier and less bubbly texture.
While it is not essential, it is generally considered good form to have a light touch when finally shaping bread or pizza. By giving the bread this final forming, the baker is giving their dough every possible chance to achieve decent oven spring when baked.