I guess this allows you to choose the headphone type you want while minimizing further price increase. Samsung regularly runs promotions allowing customers to receive a gift with their purchase. I for example prefer the Galaxy Buds Live as they don't completely obstruct the ear canal and can be worn for hours. While the Buds Pro likely have a better sound I wouldn't wish them as a gift, same with the usual earphones Samsung used to include. I know you could always sell them, but I prefer having a choice which is the whole idea of being in the Android ecosystem compared to other manufacturers who sell their users intangible privacy propaganda.
On another note, Samsung's web shop does show what's included in the box and so do Samsung's official unboxing videos on YouTube.