Specification says it has playback compatibility of DVD, DVD-R/RW, DVD+R/RW, DivX and MP3 any media can be played on this device. The specification refers to the capability of the DVD player not the USB hub.
The DVD player can read those types of discs but you still need a software player in order to play them on your pc.
The same applies to the USB hub. It simply another convenient USB port. It has no built in software
to use to play files that need a player. It is simply a port that you can use with any USB device .
Ordinarily you would download files that require a player on to your hard drive into a folder where you can keep them organized and then when you click on one it will launch the program needed or ask you which program you want to use from a list that the finds. It becomes the chosen one after then.
Bottom line- The DVD drive is for reading certain types of files that have been recorded on the disc but you still need player software such as Windows Media Player in order to play them.
Bottom line- The USB port is just an additional port that is in a handy place.
You could have before buying the player and still can download youtube files and play them totally without the new player.
You will need appropriate software-not hardware-