Hi @thl-cmk !
The description from the uploaded file is shown in the version description and the one above is the general package description that is shown on the exchange for all versions, and is stable (unless you want to change it within the Exchange).
A lot of the version descriptions I saw were mostly applicable to a specific version – for example they include a short changelog or some pointers on how to use the plugin efficiently in this specific version. While the general description is there to simply state what is the higher level purpose of the plugin.
Can be the very same text though, if you prefer it this way 
Edit: the general description also allows for more formatting, adding pictures and much more, again – if you wish to do so