I didn't need it either. But like any smart system builder I have planned ahead. Future expansion will require more power. So I budgeted in a PSU with room to spare.
If you get a PSU with just enough power to push your basic setup, in the future when you add some power hungry devices, you wind up having to replace the old with a new high power one. Why spend twice when spending once is smarter?
As for the ASUS Blu-ray it's just a little pricey at 58.99. While the LG has the same specs at 39.99. A savings of 19.00 US dollars. Take that and put it toward the PSU.
If you stop to compare specs on devices you'll find quite a few have the same specs. And that you can get the same device for a lot less. Brand loyalty is all fine and good, but once you peel back the name brand you find a lot of private labeling going on. Knowing who is making those products can lead you to the source and better prices.
. i stand corrected lol. 
