Really dumb question on Belkin 7-port USB hub... (1 Viewer)

So we know what I'm talking about...

http://www.amazon.com/Belkin-Ultra-Slim-7-Port-USB-2-0/dp/B005A0B4B4/ref=sr_1_18?s=pc&ie=UTF8&qid=1381009418&sr=1-18&keywords=7+port+usb

Not exactly the "techie" type...especially on minutiae.

Why is this powered?

This thing has no instructions(Belkin.com is no help either).

Is it so it can be a charger if not connected USB?

By the way, bought it for an iMac(new retina display) but the iPad is connected directly to the iMac. This is for all the other peripheral stuff(had a cheapo 5-port).

Can it be used w/o the power brick?

None of the Amazon Q/A answer the basic question. Bought it at BB anyway...cause I needed/wanted it today.

Why is it powered? Because many devices draw base power (like 2.5" HDD) having 7 of such devices exceeds a single USB port maximum (the one it's cloning).

You could use it without power, but you could only use LPDs (Low Power Devices). Think KB, Mice, Printers... no HDDs, imaging devices, phones, ipods, tablets.