More rising time makes a chewier bread.
The extra yeast makes it light.
I think the longer rising time can make a very light bread, but the reason for less yeast is so that the bread develops better flavor.
A lot of yeast can make a bread light, but it will taste more of yeast than the nutty flavor of the wheat, which develops a wonderful flavor if allowed several long cool rises.
If there is a lot of sugar and other stuff in the bread, long rises aren’t possible, though. The long rises are best with the simple rustica breads, like italian, cuban, french, etc.
My biggest challenge is to make excellent Ciabatta. It calls for a very wet and sloppy dough, and a biga with a 24 hour rise. I always get more flour in it, and then don’t get those big yummy holes.