Hello Jonathan!
Thanks for comment
This feature was implement in case of quick access to store data in case of store switching.
See screenshot -
http://screencast.com/t/BRHQLDPQXO
If you have 1 store with 100 products and another one with 100 000 . in this case it better to represent standard amount of data (20 row in this case) it quickly and you can see necessary data.
By the way -you can turn paginator off by this button - see screenshot -
http://screencast.com/t/1teTTNEg6N7
Button - "Show\Hide Page Filter"