Layered pieces in??

I’m not one to shame a fashion style but recently brands (Dfyne w/ the Sav edit, Oner’s summer heat collection, YoungLA for her butter soft collection) have been styling their new lines by double layering pieces.

For those of you that do it- is it even comfortable?

For example- Dfyne layered leggings on top of eachother… idk I just feel like this would be SO uncomfortable. Or double layering sports bras.

I just can’t comprehend why they wouldn’t create a single piece with the double layered effect instead. Unless to obviously sell more product (which by itself sells out within minutes).

Any benefits to layering? Or pure aesthetics?