Interesting, do you have a link to it? Im curious how they rigged it up to get it to work.
Is this the one you found?http://www.mwave.com/mwave/SKUSearch.asp?scriteria=BA31290&pagetitle=COOLMAX%20PS-200%20graphic%20card%20protector%20surge%20suppressor
Looking at the specs, yes it is indeed a surge suppressor. An effective and useful surge suppressor? No, not at all. It won't stop any voltage spikes below 14.5 V which are still plenty high to cook your GPU, it also has a current limiter set at 19 A, a 6 pin PCI-e connector is meant to carry 6.25 A so that is awfully high.
The problem with an internal surge suppressor is that 2 volts extra is enough to seriously hurt computer components, but you can't make a surge suppressor to stop everything over 13 V as it will be stressed by normal operating conditions and will fail reasonably quickly. The surge suppressors in your house won't kick in until around 400 Vrms so that they don't get killed off during normal operation. For low voltage operation it is hard to make a surge suppressor with a tight enough range to stop all damaging spikes and a large enough margin to not unduly stress it with normal operation.