When something is AS IS

When something is AS IS, we often think of a comparison. I'm not sure, we usually use AS in this way, but what about "AS IS"? 

Let's look at an ad from ebay

As you can see, SOLD AS IS is put in capital letters indicating importance. But why? They don't want to fool the potential buyer into believing that everything works on the unit for sure. Maybe it does, maybe it doesn't. Nobody knows. Is this a Scam? No, because not all the time when you're selling something do you have all of the equipment to run it. It's a cut throat business out there so buy what you think is right!

Other conditions can be USED, NEW, or MINT CONDITION.