The first advantage is: the downloading of videos in FLV format, one of the most widely used nowadays, for Web video libraries. To download the video you will only have to enter the URL (correctly, you can use the copy paste function), and download.
The second remarkable advantage is: the possibility of playing the files you have downloaded without any need for a third application such as a player, and doubt as to whether it can play them or not.
The good thing about the player is that it does not require a third-party application, but its disadvantage is that it supports only 20 files.
If you want to get great many videos, Z-Player is an application worthwhile trying.
Programs related to Z-Player
Windows Media Player Firefox Plugin
Cool DVD Player
Ashampoo Media Player+
Type of license
Checked against Virus