This has been missing from Virtuemart all along... If you don't want to fondle with Excel but want to do your stuff online, this is the one.
Ease of use
List all your products per category, status, stock or however you like it, filter it and edit your stock right there on the spot!
You wouldn't need it anyway, but had an instant reply on facebook and a quick modification the next day - that's quick!
You don't need it. It is straight-forward intuitive right out of the box.
Value for money
If you have a large webshop and do not want to loose time restocking (opening every item, edit stock, saving, next item), use this instead!