[Mr Dalton]

It's a little like normal stealth, except I think that even someone who isn't actively looking for you might notice you. I'd have to check.
Plus, you can still do things while in stealth, I think. You could draw a weapon, for example, without giving yourself away, but this would break the dimming effect because you're doing something that's not unobtrusive; a person drawing a weapon isn't something you would ever ignore.
The idea is that it's supposed to be more limited than stealth in some ways, but you have the advantage that you don't need cover or some way to stay out of sight. And it would fool senses not normally fooled by stealth, such as smell. A wolf, for example, would still smell you while you were using this skill but it would ignore you unless you did something that made it feel threatened.