The point of it...
The idea is to share all relevant detail, e.g. with other software, or with other versions of WordSmith. A word list exported like this will contain not only the words in the word list, but also all the statistics, a list of the file-names, and any notes you've made.
How to do it
Relevant tools offer a menu item: File | Export data...
If you click OK, the whole set gets saved in plain text and put into a .zip file.
opening that you will see something like
with each section separated. The key words list looks like this: