Why: All of the existing headsets go over the head. Some users (women specifically) do not like over-the-head options. Some users find the existing option hurt their ears or makes them sweaty. The new 900 series headset is aesthetically unpleasing for users with smaller heads.
Personally, I keep defaulting back to my air pods as a headset solution. However, since I don't have a MAC I am unable to switch between my computer and cell phone easily. I would love a similar solution for Cisco with all the bells and whistles that Cisco provides for its headsets.