I believe this to be 100% true. When I explain to people what is going on in the dough when you are allowing it to sit and rise, I break the processes into two categories: fermentation and maturation. On a very basic level, the fermentation process is the work that the yeast does, while maturation is the work done by enzymes that are naturally present in flour breaking down the gluten proteins formed when you make a dough.
The warmer the dough, the faster the fermentation occurs. The maturation process, on the other hand, occurs at the same rate no matter the temperature. So when you cold ferment, you slow down the work of the yeast to give the maturation process more time to occur. A more mature dough means more breaking down of the gluten proteins, which means a less dense crumb, and less work for our digestive systems when we eat it. It also affects how the dough cooks, ensuring that your dough gets cooked throughout during the baking process, and you don’t have a gum line . Again, this is a fairly high level explanation, but I think it helps one understand much better the reason for cold fermenting